Marcus Andrew Semien
- Bats Right, Throws Right
- Height 6' 1", Weight 190 lb.
- School University of California, Berkeley
- High School St. Mary's High School (Berkeley)
- Debut September 4, 2013
Marcus Semien was the Southern League Player of the Year with the Birmingham Barons in 2013, when he hit .290 with 21 doubles, 5 triples and 5 homers, scored 90 runs and drove in 49 in 105 games. He earned a promotion to the AAA Charlotte Knights late in the season and hit .264 in 32 games, then got to make his major league debut with the Chicago White Sox in September, hitting .261 in 21 games.
On September 11, 2014, playing for the Chicago White Sox, Semien hit a solo homer off Scott Kazmir of the Oakland Athletics in the 6th inning to account for the only run in a 1-0 victory. His long ball backed up an outstanding performance by Chris Sale and Jake Petricka, who combined on a three-hit shutout. He hit .234 in 64 games, with 6 homers and 28 RBI. He split his time between third base, his natural position, and second base, where the White Sox had a void following the departure of Gordon Beckham in mid-season. He had started the season in Chicago but was hitting only .218 on June 1st, when he was sent down to Charlotte for a spell. He hit .267 in 83 games, with 20 doubles and 15 homers,and was back in Chicago and playing regularly in September.
On December 8, 2014, Semien was rumored to be one of three prospects traded to the Oakland Athletics for Jeff Samardzija. It was a good situation for him, as the A's had traded 3B Josh Donaldson earlier that off-season and also had a hole at second base where incumbents Eric Sogard and Alberto Callaspo had both struggled with the bat in 2014. It was the fielding side of the job that gave Marcus trouble in 2015 however. On May 21st, he had committed 16 errors, easily the most in the majors, putting him on a pace to make over 60 in a full season. His defensive woes received plenty of notice as the A's as a team were playing very poorly, and were leading the majors in errors. On the plus side, he was one of the team's few players to be hitting well, as his average was .302, with 9 doubles, 2 triples and 6 homers; but for one additional double, that was the total number of extra-base hits he had hit in 2014, in some 60 additional at-bats.