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. He ended the year at .257 in 155 games, with 23 doubles, 7 triples and 15 homers.
From 2016 to 2018 he settled into being a solid but unheralded player with the A's, playing 159 games the first and last of these seasons, but being limited to 85 games by an injury in 2017. His OPS+ figures were very consistent, with 99, 97 and 95, after being at 98 in 2015, but they were achieved in different ways. In 2016, he had an outburst of power with 27 homers, compensating for a batting average falling to .238. He increased that to .249 and .255 the next two years even if his power went down, and his walk rate also improved. The A's made it to the postseason as the second Wild Card team in 2018 and he made his postseason debut in the Wild Card Game against the New York Yankees that year, going 1 for 3 with a walk.
Marcus had his best season in 2019 when he finished third in the MVP voting. He hit .285 while played all 162 games, led the American League in plate appearances with 747 and contributed plenty of power with 43 doubles, 7 triples and 33 homers. He scored 123 runs as Oakland's lead-off hitter and also drove in 92, and drew 87 walks for an OPS+ of 139. The A's were back in the Wild Card Game, but he made another early exit as they were defeated by the Tampa Bay Rays. He was 1 for 5 with a run scored in the game. He fell back to his previous level of production in 2020 when he played 53 of his team's 60 games during a season shortened by the Coronavirus pandemic. His batting average fell to .223, but he maintained decent power with 9 doubles and 7 homers and also drew 25 walks for an OPS+ of 91. This time, the Athletics managed to make it a bit further in the postseason: he was 3 for 12 with a double and a homer in their defeat of the Chicago White Sox in the Wild Card Series, and 8 for 15 with 4 runs in their loss to the Houston Astros in the Division Series. Following the season, he became a free agent and on January 26, 2021 signed a one-year deal with the Toronto Blue Jays for $18 million. He was expected to move to second base for the Jays, with young Bo Bichette at shortstop and Cavan Biggio becoming a super utility player.
Semien was the first batter of the 2021 season as the Jays' leadoff hitter in their game against the New York Yankees at New Yankee Stadium on April 1st. The game had the earliest starting time among the full slate of games scheduled that day. After a so-so first month, he had a great May, batting .368 with an OPS of 1.130, 8 homers and 22 RBIs in 28 games and was named the American League Player of the Month. Two of his main rivals for the honor were teammates, namely Vladimir Guerrero Jr. and Teoscar Hernandez. He was voted as the starting second baseman for the 2021 All-Star Game. On August 7th, he hit his first career walk-off homer connecting off Matt Barnes of the Boston Red Sox on the first pitch of the bottom of the 7th inning to give the Blue Jays a 1-0 win in the first game of a doubleheader at the Rogers Centre. By then, he had been moved to the third spot of the batting order, as a healthy George Springerhad reclaimed his customary leadoff spot, but that had not slowed down Marcus in any way, as he continued to pound the ball with the best hitters on the AL. He was voted a starter in the All-Star Game, his first participation in the mid-summer classic, and continued to pound the ball in the second half. On September 18th, he hit home run #40 in a win over the Minnesota Twins at the Rogers Centre. He was only the fourth second baseman in major league history to hit that many in a season, the record of 43 having been set by Davey Johnson in 1973.
- 2013 Player of the Year Southern League Birmingham Barons
- AL All-Star (2021)
- 20-Home Run Seasons: 2 (2016 & 2019)
- 30-Home Run Seasons: 1 (2019)
- 100 Runs Scored Seasons: 1 (2019)
- Keegan Matheson: "Blue Jays add Semien on 1-year deal (source)", mlb.com, January 26, 2021. 
- Keegan Matheson: "How Semien fits with Blue Jays' young core", mlb.com, February 2, 2021. 
- Keegan Matheson: "Semien in exclusive company with 40th HR: Second baseman nears single-season HR record for 2B", mlb.com, September 18, 2021. 
- Mike Petriello: "Why Semien at 2B should be a good fit", mlb.com, February 17, 2021.