Bud Selig, who insisted in the past that he planned to leave his post as baseball commissioner when his current term expired in 2009, was extended for three more years this morning in a unanimous vote of team owners in Phoenix.

Selig, who will be 78 when the new extension expires, will have served as commissioner for 20 years, including six in an interim capacity. His contract was extended through 2009 on August 21, 2004, and the Milwaukee native said at the time that he planned to retire at the end of that term.

In December 2006, Selig reiterated his plans to retire in 2009. But owners continued to prod him to leave the door open to an extension.

The timing of the extension is the owners’ way of showing their support for Selig despite the recent scandal involving use of performance-enhancing drugs in baseball. Selig appeared before Congress on Tuesday to testify about the Mitchell Report, which he commissioned to investigate past use of steroids and other banned substances in baseball.

Selig and players union chief Don Fehr both accepted responsibility at that hearing for their roles as the game’s leaders during what is now know as “The Steroid Era.”

Selig’s new deal would expire in 2012.