NASHVILLE, Tenn. (AP) — Vanderbilt coach Derek Mason has fired defensive coordinator David Kotulski, making him the fourth assistant let go since the season ended.

Mason announced the move Monday.

Mason brought Kotulski with him from Stanford, and Kotulski also coached inside linebackers at Vanderbilt. The men first worked together at Bucknell in the 1990s, and Kotulski was linebackers coach at Stanford when Mason was defensive coordinator in 2012 and 2013.

The Vanderbilt coach called Kotulski a very close friend and true mentor, and Mason said he appreciates his help this past year.

Mason already fired offensive coordinator and quarterbacks coach Karl Dorrell, receivers coach Marc Lubick and conditioning coach Bill Hughan.

Vanderbilt went 3-9 in Mason's first season, losing all eight Southeastern Conference games for the first time since 2009.