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SAN FRANCISCO -- Two teams that imported Jeff Samardzija for runs at a World Series title meet Monday night when the rival Oakland Athletics and San Francisco Giants begin their annual interleague series.

The first-place Giants (49-28), having won 13 of their last 16 at home, will host the first two games of the four-day affair.

The fourth-place A's (32-43), coming off a 3-1 series win in Anaheim against the Angels, will be the home team Wednesday and Thursday when the battle for San Francisco Bay Area bragging rights concludes in Oakland.

Samardzija joined the A's from the Chicago Cubs on July 5, 2014, at a hefty price when Oakland general manager Billy Beane agreed to part with one of the franchise's top prospects, shortstop Addison Russell.

The A's went on to capture a wild-card berth into the 2014 American League playoffs even though Samardzija went just 5-6 with a 3.14 ERA in 16 starts.

He was pitching his best ball at the end of the season, having not allowed an earned run over a 22-inning, three-game stretch during a key September sequence.

He was in line to pitch Game 2 of the AL Divisional Series had the A's, with Jon Lester on the mound, not blown a 7-3 lead in a 12-inning loss to Kansas City in the AL wild-card game.

Samardzija was dealt to the Chicago White Sox two months later, allowing the A's to acquire a new shortstop, Marcus Semien.

Semien led all of baseball with 35 errors last season as the A's went from an 88-game playoff team to a 68-win last-place club.

Semien made only eight errors in 75 games this season, but the A's winning percentage (.427) is only marginally better than last year's .420 mark.

Samardzija, meanwhile, returned to the Bay Area exactly a year after being dealt by the A's, signing a five-year, $90 million free-agent deal with the Giants.

Coupled with the addition of Johnny Cueto from Kansas City, the Giants enter play Monday with the most wins in the National League (49) in their quest for a fourth World Series championship since 2010.

Samardzija has played a role in the fast start, going 8-4 with a 3.59 ERA.

The former Notre Dame wide receiver says he will be excited about Monday's outing for more than just seeing the A's again. He's coming off the shortest start of his career -- three innings at Pittsburgh -- and admitted afterward he owes his teammates one after they bailed him out in a 7-6 win.

"It says a lot about this team, both the bullpen and the offense, when you can pitch a crummy game like I did and we were still able to come away with a win," he said afterward. "It means a lot and I'm going to remember it."

Samardzija has split decisions against the A's since his brief stint with them, including a 7-3 victory last season on May 17 in his only Bay Area return before joining the Giants.

The A's extracted a measure of revenge when they saw their old pal in Chicago on Sept. 15, bombing him for 10 runs on 11 hits over three innings in a 17-6 shellacking.

The A's have scored 10 or more runs just three times since then, but never more than 14.

Oakland will counter Monday with right-hander Daniel Mengden (0-3), a rookie who was acquired from the Houston Astros in a deal involving another of the club's key starters in the 2014 playoff run, Scott Kazmir.

Mengden has pitched a lot better than his record would indicate, A's manager Bob Melvin assured reporters after Wednesday's 4-2 loss to the Milwaukee Brewers.

"He knows we think he's good, and he is," Melvin insisted. "He knows he's good, too. He might not tell you that, but he knows he's good."