CLEVELAND, Ohio -- The Indians could lose more than the AL Division Series now that the offseason has officially begun.

Two of their top pitching coaches could be headed elsewhere. Mickey Callaway, the Tribe's big-league pitching coach, has been rumored to be managerial candidate for a number of teams. The Phillies, it has been learned, have officially asked for permission to talk to Callaway and he's expected to interview with them in the near future.

ESPN's Buster Olney was first to report the Phillies' interest in Callaway.

Phillies taking a close look at Indians pitching coach Mickey Callaway as they look for their next manager. — Buster Olney (@Buster_ESPN) October 12, 2017

Ruben Niebla, the Indians minor league pitching coordinator, has also been approached about a big-league coaching job from another team. Niebla has been with the Indians for the last 17 years and has worked with a lot of pitchers on the current big-league staff.

The Phillies, who have an impressive array of young talent and a good farm system, created the vacancy at manager when they moved Pete Mackanin into a front office job at the end of this season.

Indians pitchers have flourished under Callaway, 42. This year the Tribe's rotation went 81-38 and posted the top ERA in the AL at 3.52. The bullpen also led the AL in ERA at 2.89.

The rotation boasted two 18-game winners in Corey Kluber and Carlos Carrasco and a 17-game winner in Trevor Bauer. The rotation had five pitchers with 10 or more wins when Mike Clevinger (12-6) and Josh Tomlin (10-9) were included.

The Indians were the only team in the big leagues to have that many pitchers with 10 or more wins.

The staff's 3.30 ERA was the lowest in the big leagues. It was the first time the Indians have done that since 1954. They also set a big-league record with 1,614 strikeouts, while allowing the fewest walks in the big leagues with 406.

Niebla, 47, has played a big role in developing pitchers such as Kluber, Clevinger, Tomlin, Carrasco and Danny Salazar. He served as the Indians' interim pitching coach in 2012 after Scott Radinsky was fired.

If Callaway leaves, it will be interesting to see if John Farrell will replace him. Farrell, fired as Boston's manager on Wednesday, was Francona's pitching coach in Boston. They were teammates on the 1988 Indians.

Farrell was drafted and pitched for the Indians. He served as their farm director before joining Francona in Boston as his pitching coach.