Eiland, 43, enters his third season as the Yankees' pitching coach and eighth year coaching in the organization, as his pitchers ranked fourth in the American League with a 4.26 ERA in 2009. Harkey, 43, will begin his third season as the Yankees' bullpen coach.
Kelleher, 62, will return for his second year as New York's first-base coach and fifth year as a coach or instructor in the organization, having been instrumental in helping the Yankees set a Major League record with 18 consecutive games without committing an error in 2009.
Long, 43, will return for his fourth season as the hitting coach and seventh year in the organization, following a year when he presided over an offense that led the Majors with 915 runs, 244 homers, a .478 slugging percentage, a .326 on-base percentage and 663 walks.
Pena, 52, will return for his fifth season on the Yankees' Major League coaching staff and second as bench coach, also contributing as the catching instructor for a roster that tied for third in the AL with 38 caught stealing and fifth with a 23.3 percent caught-stealing rate.
Thomson, 46, will enter his 21st season in the Yankees' organization and his second as third-base coach.
New York also announced on Wednesday that the field staff of the Triple-A Scranton/Wilkes-Barre Yankees would remain the same, with Dave Miley returning for his fifth season as manager, along with hitting coach Butch Wynegar, pitching coach Scott Aldred, infield coach Aaron Ledesma, athletic trainer Darren London and strength and conditioning coach Lee Tressel.
"It's a big plus to have the continuity of all of our field staff returning in 2010," said Yankees senior vice president of baseball operations Mark Newman. "As a group they have done a really great job negotiating their way through the ups and downs of a season with roster moves and all of the other things that you run into. They are great coaches and great teachers who understand our system organization's philosophies."
Additionally, Torre Tyson will return for his fourth season as the manager of the Class A Charleston Riverdogs, along with pitching coach Jeff Ware. Carlos Mendoza will serve as the first-base coach at Charleston.