CHICAGO -- Jeff Samardzija will find himself on a familiar mound but in an unaccustomed role on Thursday.

A onetime baseball and football standout from northwest Indiana and a Chicago Cubs pitching mainstay from 2008 to 2014, Samardzija will try to shut down his former team as the San Francisco Giants arrive for the opener of a four-game weekend series.

The 31-year-old Samardzija, in his first season with the Giants, faces his former team for only the second time in his career and first at Wrigley Field at 8:05 p.m. ET Thursday.

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"I'm sure he's excited about it," San Francisco manager Bruce Bochy said Wednesday. "He's spent some time there. He knows Wrigley Field. He's been throwing the ball well. I hope he continues that into tomorrow's game."

The Giants, currently leading the National League wild-card standings, are making their only Wrigley Field appearance of the season.They took two of three from the Cubs on May 20-22 at AT&T Park.

Samardzija declined a long-term Cubs offer in 2014 and began an odyssey that took him to Oakland (via trade), to the Chicago White Sox last year and finally this season to the Giants.

Set to make his 26th start of 2016, Samardzija is coming off a seven-inning shutout performance on Aug. 26 against the Atlanta Braves that included seven hits, six strikeouts and three walks.

He's 0-1 all-time against the Cubs, suffering the loss on Aug. 14, 2015, when the White Sox beat their cross-town rivals 6-5 at U.S. Cellular Field.

The Cubs counter with Mike Montgomery (1-1, 3.50 ERA), who was originally slated to pitch Wednesday but swapped spots with Jason Hammel.

Montgomery, 27, makes his third start with the Cubs, all against NL West opponents, including two against the Giants. He threw 91 pitches, allowed three runs despite walking four and gave up six hits in a no-decision on Aug. 26 at the Los Angeles Dodgers, a 6-4 extra-innings victory.

"I decided to give him an extra day," Cubs manager Joe Maddon told reporters. "It just made all the sense in the world to do it that way. I talked to Hammer (Jason Hammel) about it yesterday, and he was fine. Montgomery was good with it, so that's what we're going to do."

Montgomery has made 20 career starts, going 5-7 with a 4.39 ERA and two complete game shutouts in 2015.

Chicago's spacious new clubhouse will easily handle additions arriving this week as rosters expand to 40 on Thursday.

The Cubs got the jump on added personnel by recalling versatile infielder Tommy La Stella and his .295 bat from Triple-A Iowa and inserting him in Wednesday lineup.

LaStella had played in 51 games before a declining to report as assigned to Triple-A Iowa in late July, then later agreeing to a minor league stint.

He's expected to be a frequent September contributor and through the subsequent NL playoffs.

After the series against the Giants, the Cubs embark on a 10-day, nine-game road trip that takes them to Milwaukee, Houston and St. Louis.