(SportsNetwork.com) - There was no better story in baseball last season than the Kansas City Royals' return to the postseason and their run to an American League pennant.

They'll start defense of their AL crown on Monday when they welcome the Chicago White Sox to Kauffman Stadium.

Kansas City's magical season, of course, ended in bitter disappointment, as it lost at home in Game 7 in the World Series. Still, once the dust settled, few were left complaining considering the team hadn't been to the playoffs since 1985.

The Royals, though, may have a difficult time getting back there, as ace and team leader James Shields left as a free agent to join the San Diego Padres, while longtime Royals fixture Billy Butler signed with the Oakland Athletics as a free agent.

What made the Royals trip to the playoffs so unexpected was that they advanced despite down offensive years from key youngsters such as Salvador Perez, Eric Hosmer and Mike Moustakas, all of whom are returning and from whom Kansas City can reasonably expect some improvement.

What Kansas City did do better than anyone was play defense. The Royals' defense, which ranked second in the AL with 41 Defensive Runs Saved, returns largely intact, with Alex Rios providing an upgrade in right field on the always adventurous Nori Aoki.

But the real reason the Royals made it as far as they did was due in large part to one of the more dominant bullpen triumvirates in recent history. Closer Greg Holland and setup men Wade Davis and Kelvin Herrera put up historic numbers last season, and if they do the same this year Kansas City could once again be playing October baseball.

With Shields now in San Diego, 23-year-old Yordano Ventura will get the call on Monday.

Ventura, who pitched six scoreless innings in Game 6 of last year's World Series, made 30 starts and lasted 183 innings in 2014, with a 14-10 record and a 3.20 ERA. He posted an identical ERA in 25 1/3 postseason innings.

Kansas City recently locked up their young ace with a 5-year extension with two options years that could keep him h in Kansas City through 2021.

No team in the AL changed themselves more than the White Sox. And it's not because the roster won't include Paul Konerko for the first time since 1999.

After a 73-89 finish in 2014, Chicago general manager Rick Hahn doled out $132 million to five free agents: outfielder Melky Cabrera, first baseman Adam LaRoche, utilityman Emilio Bonifacio, closer David Robertson and lefty reliever Zach Duke.

That doesn't even include the December trade for Jeff Samardzija.

Regardless of the new faces in the locker room, reigning AL Rookie of the Year Jose Abreu is now THE face of this franchise in the wake of Konerko's retirement. The Cuban slugger burst upon the scene last season, hitting .317 with 36 HR, 107 RBI, a .581 slugging percentage and a .964 OPS.

Samardzija would be an ace on a lot of teams, but not this one. Left-hander Chris Sale is as good as it gets, but the start of his season will be delayed thanks to an avulsion fracture and sprained right foot.

So, with Sale out, Samardzija gets the call on Monday. He posted a 2.99 ERA and 1.065 WHIP in 219 2/3 innings last year between the Cubs and Athletics.

"Everybody looks forward to their first start of the year whether it's the first, second, third, fourth or fifth -- whatever game of the year it is," he said. "After that first time through the rotation, with off days, everything gets mixed up and you're not always matching up with the other team's No. 1 or No. 2 starters.

"The first time out everything works in order. It doesn't really mean much after that."