Tennessee Titans coach Mike Munchak fired offensive coordinator Mike Heimerdinger and two other assistants on Tuesday as he starts to remake his coaching staff a day after taking over the top job.

Heimerdinger, who is continuing cancer treatment after being diagnosed in November, confirmed to The Associated Press on Tuesday that he had been fired.

"It's never easy to be fired," Heimerdinger said. "He has to do what's good for the Titans, and Munch will do what's best for the Titans. I appreciate my time here, but it's never easy to be fired."

The Titans also announced that defensive assistant Rayna Stewart and offensive assistant Richie Wessmanhad won't return.

"I met with Mike, Rayna and Richie today and informed them that they would not be retained as a part of the new staff," Munchak said. "These are not easy decisions, but I have a responsibility to move things in the direction that I have laid out for this team. We will continue to evaluate the rest of the staff moving forward.

"As it relates to Mike, I have a great deal of respect for him as a person and admiration for the way he is fighting against cancer. He is an innovative offensive mind and we have worked well through the years, but I believe we need to go in a different direction at offensive coordinator. This wasn't about his health -- he is feeling good -- it is a change of direction for us. This is not something that I take lightly and I wish him and his family the best."

Munchak promised that changes were coming when he was introduced Monday. Heimerdinger, under contract for 2011, was the second coach the Titans interviewed to replace Jeff Fisher. After Munchak was hired, Heimerdinger said he was happy that Munchak got the job.

As did Fisher, who told the The Tennessean on Tuesday that he supported the Titans' decision to promote Munchak.

"I believe they made the right choice," Fisher said. "Munch has been in the league for a long time as a player and a coach, and he is regarded as one of the top, if not the top offensive line coaches in the league.

"I have confidence in him and think he'll do a great job. Mike and I are good friends, and he has been with this organization longer than I was. Whatever I can do for Mike in the future, I'd be more than willing to help. But he's going to do a great job."

Munchak signaled Monday that he wasn't committed to keeping anyone on the coaching staff, and the Titans gave him freedom to keep or hire anyone he wants. Munchak said anything is possible when asked specifically about Heimerdinger.

"I feel like we're starting fresh," Munchak said Monday. "It's not the same-old, same-old."

Fisher acknowledged that Munchak likely would need to make some changes.

"Mike knows what he needs to do moving forward, and understands what changes need to be made," Fisher said. "He has some challenges ahead as far as putting his staff together, but I know Mike is going to make the right decisions as far as potential staff changes."

The firing of Heimerdinger gives Munchak six openings to fill on his coaching staff. Fisher fired defensive coordinator Chuck Cecil last month, while the defensive line coach, running backs coach and wide receivers assistant all left for other jobs.

Former teammate Bruce Matthews, now an assistant in Houston, is expected to be Munchak's top target to fill his old job with the offensive line, and the Houston Chronicle reported Tuesday that the Titans have told the Texans they plan to interview Matthews, who has agreed to but not signed a two-year contract with Houston.

The news of Heimerdinger's firing brought almost instant reaction Tuesday.

Titans safety Michael Griffin wrote on Twitter that, "People thought it was a joke when I said no one is safe."

This was Heimerdinger's second stint as offensive coordinator with Tennessee. He helped the late Steve McNair earn co-MVP honors in 2003 and was part of three playoff teams in his first five seasons before leaving for the same job with the Jets in 2005. Fisher brought him back in 2008 after two seasons in Denver.

The Titans set a franchise-low with 12 sacks allowed in his first season back. The Titans racked up the second-most yards rushing in franchise history in 2009 when Chris Johnson set the NFL record for yards from scrimmage with 2,509 while earning the AP NFL Offensive Player of the Year award.

Heimerdinger kept coaching and didn't miss a game after being diagnosed with a rare cancer the day before Thanksgiving. Fisher extended his coordinator's contract before the season ended.

The Titans' offense struggled in 2010, ranking 27th in the NFL in total yards per game (302.1) and 25th in yards passing (194.2). Johnson couldn't help the rushing attack much with just 107.9 yards averaged per game (17th overall).

Worse, the Titans rank last in time of possession, holding the ball just 25 minutes, 54 seconds per game. Tennessee was limited by injuries at quarterback, including the season-ending thumb injury to Vince Young on Nov. 21.

Asked about his offensive philosophy Monday, Munchak said the Titans have to stay on the field no matter what they do on offense.

"We struggled last year to stay on the field as an offense," Munchak said. "I'm stating the obvious. But we need to find a way, whatever that offense is, whatever that system is, we have to make first downs and stay out there."

The Associated Press contributed to this report.