Mark Kotsay, who spent the previous three seasons as the A's quality control coach, will return to the third-base coach's box next year. The A's announced their 2021 coaching staff Thursday, with Kotsay returning to coach third base, as he did from 2016-17 on manager Bob Melvin's staff.

Kotsay, who's in his sixth season with the A's, will share infield and defensive positioning duties with hitting coach Eric Martins. Also returning to the staff next year is hitting coach Darren Bush, who will be in his seventh season as hitting coach. He's the longest tenured hitting coach in Oakland history and his nine seasons as a coach are tied for sixth most in club history.

Meanwhile, Scott Emerson returns as the A's pitching coach for his 19th season in the A's organization, and Ryan Christenson is back for his fourth season as Melvin's bench coach. The 2021 season will be Christenson's 16th in the A's organization, which includes five years as a Minor League manager and seven seasons as a player.

Mike Aldrete returns for his fourth season as Oakland's first-base coach, and bullpen coach Marcus Jensen returns for his seventh season after joining the staff as assistant hitting/catching coach in 2015.

This will be Martins' 21st season in the A's organization, which includes seven years as a Minor League player, seven years as an area scout and five years as a Minor League hitting coach.