National League baseball fans have learned to expect the unexpected the past two seasons.

Be honest. Did you think the San Francisco Giants would bring home the World Series title in 2010? While we're at it, did you really think the St. Louis Cardinals would capture the crown last fall?

Unpredictability is the main reason we watch sports, and NL baseball fans additionally have their share of exciting players to watch for the 2012 season.

Here's a look at players who will go a long way toward determining their team's ultimate success this year:

ARIZONA - PAUL GOLDSCHMIDT: The Diamondbacks took charge in the NL West last season despite getting subpar offense from the first base position. That was until Goldschmidt was called up to The Show in August. Goldschmidt occasionally flashed the prodigious power he displayed in the minors, belting eight home runs and driving in 26 runs in 156 big-league at-bats. It was a noticeable upgrade over the other five first basemen the Snakes employed (a combined 16 homers in 513 at-bats). In a Division Series loss to the Milwaukee Brewers, Goldschmidt went 7-for-16 with two homers, six RBIs and a 1.339 OPS. Sure, he struck out too much (53 times in 177 plate appearances), but the potential is there for him to provide yet another power bat to a lineup that, despite its offensive deficiencies at first base, was fourth in the league with 731 runs scored.

ATLANTA - JASON HEYWARD: The Braves are loaded with young talent on the rise. An influx of pitchers currently toiling in the minor leagues is soon on the way. Offensively, Atlanta's young stud figures to be Heyward, who is still just 22 years old. After an impressive rookie season in 2010 (.277, 18 homers, 72 RBIs), Heyward slumped to .227, 14 homers and 42 RBIs last year. The left- handed hitter had a miserable .578 OPS against left-handed pitching, and he batted a meager .218 with runners in scoring position. He's young and a five- tool talent, so it would be best to give him the benefit of the doubt. Remember, the majority of players at Heyward's age haven't even reached the majors yet. He'll be fine.

CHICAGO - CARLOS MARMOL: The Cubs have gone 103 consecutive seasons without winning a World Series title. It's safe to say that number will increase to at least 104. This is a major rebuilding project for new team president Theo Epstein, whose team could be one of the worst in the majors this summer. The best way to rebuild is to have valuable trade chips who could net young talent in return. That's where Marmol comes in. On the negative side, he blew 10 saves and had an unsightly 4.01 ERA last year. On the positive side, he struck out 99 in 74 innings. In an off year, the league hit only .205 against Marmol. If he can return to 2010 form (38-for-43 in saves, 2.55 ERA, 138 strikeouts in 77 2/3 innings), he'll be quite a valuable commodity to a closer-needy team at the trade deadline.

CINCINNATI - MAT LATOS: When the Reds made the playoffs in 2010, they did so with an elite lineup and a pitching staff that featured five guys who were OK - none that would be considered a legitimate ace on a championship-caliber team. Cincinnati was swept in that NL Division Series against the Philadelphia Phillies, and it did nothing to improve the mediocre rotation in 2011. The result: no playoff appearance. Enter Latos, acquired in an offseason trade with the San Diego Padres. The Reds surrendered excellent young talent for Latos, but he could soon develop into the true No. 1 the team has lacked. In his first full major-league season with San Diego in 2010, Latos went 14-10 with a 2.92 ERA and was eighth in the Cy Young Award voting. Last year, he slumped to 9-14. Even in a down year, though, his ERA was a solid 3.47. He's going from the ultimate pitchers' haven (Petco Park) to a bandbox (Great American Ballpark), but he's a 24-year-old pitcher with 27 career wins and a 3.37 ERA and good control. If the Reds win the NL Central, he'll be the reason.

COLORADO - DEXTER FOWLER: The best of Fowler is a solid leadoff hitter/center fielder prototype. The problem is, the Rockies usually only get to see the best of Fowler for a fraction of the season. For each of the past two years, poor performance has resulted in Fowler being sent to Triple-A Colorado Springs. He was terrible in the early part of 2011. Upon returning from his demotion, he batted .288 after the All-Star break with an .880 OPS and 10 steals in 13 attempts. Fowler's just 26 years old and has the talent. If he can consistently get on base, the Rockies could conceivably field the league's best offense. The lineup figures to improve with the addition of Michael Cuddyer and the expected return to form of elite outfielder Carlos Gonzalez, who was hampered by wrist and back injuries last year. Now, if only there were so few questions about the Rockies' pitching.

HOUSTON - JOSE ALTUVE: Essentially playing out the string in their final season in the NL, the Astros aren't likely to make much noise - even in a mediocre division that includes the rebuilding Cubs and the perennial also- ran Pittsburgh Pirates. It's always fun to root for the underdog, so the most intriguing aspect of watching 2012 Astros baseball will be seeing just how well vertically challenged Altuve, their second baseman, will handle an everyday role for a full season. Usually listed at 5-foot-7 (although most estimates say he's closer to 5-5), the 22-year-old Venezuelan infielder hit a respectable .276 in 234 at-bats after his call-up last season. He only had 13 extra-base hits with the Astros, but he slugged .569 in 153 Double-A at-bats prior to that. He's fun to watch, and, really, how many Astros can that be said about?

LOS ANGELES - ANDRE ETHIER: Matt Kemp was the NL MVP runner-up for the Dodgers last year and he did it without the presence of another elite hitter in the middle of the order to help him carry the load. Kemp should be aided this season, provided Ethier can remain healthy. A physical wreck last year, Ethier for the most part played through his ailments. His reward for playing with a knee injury that finally required surgery and cut his season short? He was limited to an uncharacteristically low 11 homers and 62 RBIs in 135 games. In his three previous seasons, he averaged 25 homers. That's closer to the kind of production that Dodgers fans could expect in 2012.

MIAMI - HANLEY RAMIREZ: If you ever played Little League or high school ball, you'll likely recall that the best athletes (at least when they weren't pitching) were shortstops. Only entering his age-28 season, Hanley Ramirez is already a three-time NL All-Star shortstop. He's won a batting title (in 2009) and been in the top 11 of MVP voting three times, including a runner-up finish in 2009. The Marlins, however, have brought in ex-New York Met Jose Reyes as a free agent, and new manager Ozzie Guillen has decided Ramirez would move to third base - a position he has never played in the majors - to accommodate Reyes. By any measure, including the eye test, Reyes is the superior fielder and should play shortstop. That's not the issue. The concern is how Ramirez will handle the change, which has to feel a bit like a slap in the face to a superstar. He's been saying the right things, but it shouldn't be forgotten that Ramirez also is returning from an injury-riddled 2011 season in which he batted just .243 with 10 homers in 92 games.

MILWAUKEE - MAT GAMEL: The player Gamel is expected to replace at first base for the Brewers belted 38 homers last year, while also knocking in 120 runs and compiling a .566 slugging percentage. For this 26-year-old left-handed hitter, though, the best approach would be to realize he should not try to be another Prince Fielder. Gamel is a career .304 hitter in the minor leagues. Once considered a top prospect, he has seen his star fade, the result of his pedestrian stats (.222 average, five homers and 23 RBIs in 171 at-bats) during parts of four big-league seasons. If free agent acquisition Aramis Ramirez can help enough in the power department, perhaps Gamel could return to his minor- league, line drive-hitting ways, and Milwaukee could remain one of the NL's best offenses.

NEW YORK METS - DAVID WRIGHT: He's been the face of the Mets for a while, but the 2012 season presents a crossroads for Wright. He's been around so long that it's hard to believe he's still only 29 years old. What's even harder to believe is that his last three seasons, typically when a major-leaguer would be in his prime, have been his worst. The guy put up with his share of ridicule from home fans last year, but Wright played for a while through a stress fracture in his back and his performance suffered. Citi Field's pitcher-friendly dimensions have done him no favors, either. Now healthy, Wright could be expected to return closer to form. The question is, with the Mets in rebuilding mode, would Wright's resurgence send him out of the Big Apple? He'd bring back a big haul should the Mets put him on the trading block.

PHILADELPHIA - RYAN HOWARD: Essentially a picture of health during his major- league career, Howard has provided the Phillies with a consistent, impact bat in the middle of the order. He'll eventually do it again in 2012, but it's questionable when his season will begin. After rupturing his left Achilles tendon making the final out in the NL Division Series loss to the Cardinals, Howard knew he would not be ready for Opening Day. Most estimates have him returning sometime in May, and that would be a good scenario. If he's out longer, the Phillies' offense could really suffer. Slugger Jim Thome is back in the fold, but his 41-year-old knees and back would likely limit him to a game or two per week as Howard's replacement at first. The primary fill-in would likely be Ty Wigginton, who is a good utilityman, but he's not Howard, who has never hit fewer than 31 homers nor driven in fewer than 108 runs in any of his six full big-league seasons. A prolonged absence would be a big blow to an overrated Phillies offense. Although the perception is that they have a lineup of thumpers, the Phils ranked seventh in the NL in runs scored (713) and eighth in home runs (153) last year.

PITTSBURGH - PEDRO ALVAREZ: What a difference a year makes. In 2010, elite prospect Alvarez, the No. 2 overall pick in the 2008 draft, hit 16 homers and drove in 64 runs in 386 at-bats after getting summoned from the minors. Understandably, the Bucs' long-suffering fan base had high hopes that he'd be a lineup cornerstone for years to come. Last season, he slumped to a miserable .191 average, four homers, 19 RBIs and 80 strikeouts in 262 at-bats. Even more alarmingly, he didn't exactly dominate in his 148 at-bats at Triple-A Indianapolis (.256, five homers, 19 RBIs). When a franchise has suffered through a North American professional sports record 19 consecutive losing seasons, it gets increasingly difficult to exercise patience. However, that should remain the approach with Alvarez, although the late 2010 version of him had best re-emerge soon.

ST. LOUIS - CARLOS BELTRAN: No, free-agent acquisition Beltran is not Albert Pujols. Probably no hitter in Pujols' generation is. Still, this veteran hitter who posted an impressive .910 OPS while splitting time between the Mets and Giants last season could help the Cardinals once again have one of the league's elite offenses. Last year, when St. Louis led the NL with 762 runs scored, Pujols hit 37 homers and drove in 99 runs. Beltran batted .300 with 22 homers and 84 RBIs last season. If Beltran puts up similar numbers in 2012, the Cardinals could be quite dangerous again, given that postseason hero David Freese will likely log more playing time than he did when injuries limited him to 97 games last season, and Adam Wainwright will return from Tommy John surgery to make the starting rotation much more formidable.

SAN DIEGO - CARLOS QUENTIN: To be fair, Petco Park has been one of the main culprits, but the Padres' offense has been anemic for quite some time. Adding a guy who has hit 20 or more home runs for four consecutive seasons is a step in the right direction, but it's unlikely that Quentin, obtained from the Chicago White Sox for a pair of minor-leaguers, will conjure memories of Dave Winfield in San Diego. Expected to be the Friars' cleanup hitter, Quentin should certainly help a team that was last in the NL in homers (91) and slugging percentage (.349) last year. It's just that he was viewed as somewhat of an underachiever with the White Sox, who play 81 games in a ballpark that's essentially the opposite of Petco - the homer haven that is U.S. Cellular Field. How Quentin responds to being - the guy - in San Diego will determine how much this offense can improve.

SAN FRANCISCO - BUSTER POSEY: In trying to defend their unexpected World Series title, the Giants' offense was putrid in 2011. They were last in the NL with 570 runs scored. That's 23 less than even the woeful Padres. They wasted the efforts of pitchers Tim Lincecum, Matt Cain and Madison Bumgarner, who all could have won at least 17 games with better offensive support. San Francisco's not going to turn the situation completely around overnight, but the return to health of Posey will help significantly. After establishing himself as the team's offensive leader during its glorious 2010 postseason, Posey was limited to 185 at-bats last year, the result of a home-plate collision in which he broke his fibula and tore knee ligaments. Will he be 100 percent this season? That's hard to say. Even at 80 percent, he might still be the best offensive catcher in the league.

WASHINGTON - STEPHEN STRASBURG: This could be the most interesting team to watch this year. If Strasburg returns to pre-Tommy John surgery form and uber prospect Bryce Harper comes north from spring training with the big club, the Nationals would boast arguably the most exciting young pitcher and hitter in the game. While the beginning date of Harper's Washington career is up in the air, there's no doubt Strasburg will immediately be the Nationals' ace. If there were questions about how he'd look in a return from surgery, he answered them by making five September starts last season and pitching to a 1.50 ERA. Stay tuned for the last month of the regular season, though. The Nationals have already announced that Strasburg will be limited to about 160 innings, much like the team did with Jordan Zimmermann under similar circumstances last season. If the Nationals enter September still in the playoff chase, they'll likely have to forge ahead without their ace.