Posted by Sabrina B. @gametimegirl

The San Francisco 49ers’ eighth consecutive season without a playoff appearance has cost Mike Singletary his job as the team’s head coach.

The 49ers announced the firing Sunday night after the team returned to its Bay Area headquarters following a 25-17 defeat to the St. Louis Rams earlier in the day.

The defeat eliminated the 49ers from playoff contention, marking their eighth consecutive year without a postseason appearance. Defensive line coach Jim Tomsula will coach the team’s game against Arizona at Candlestick Park in Week 17. He was to be formally introduced in a news conference Monday.

Singletary, 52, went 5-10 this season and 8-8 in 2009, his first as head coach in full. He posted a 5-4 record as interim coach after the team fired Mike Nolan during the 2008 season.

Team president and CEO Jed York addressed reporters in St. Louis after the Niners’ loss Sunday and was noncommittal about whether Singletary would coach the final game, saying he planned to think about it. Singletary was told of his dismissal back at the team’s Santa Clara complex after the trip home.

“I want to thank Mike Singletary for the passion and effort that he brought to this organization,” York said in a statement. “He is a tremendous person for whom I will always have great respect.”

San Francisco began the year with high hopes of winning the NFC West and reaching the postseason for the first time since 2002. Singletary finished with an 18-22 record in two-plus seasons.

“One of the greatest experiences of my life was having the opportunity to coach the San Francisco 49ers,” Singletary said in a statement. “What made it so special were the players. They were some of the most outstanding men I have ever been around in my life. The coaches were truly professionals. I wish the 49ers nothing but the best. I am thankful to the York family for having given me the opportunity to be a head coach in the NFL. I am indebted to them for that. I am also thankful for the Faithful fans, I am just sorry I couldn’t give them more.”

The 49ers began 0-5 and will finish with a losing record for the seventh time in eight years. They went 8-8 in Singletary’s first full season, then produced an unbeaten preseason this year only to drop their first five games. It was the franchise’s worst start since losing seven in a row to begin a 2-14 season in 1979 — in the late Hall of Famer Bill Walsh’s first year as coach.

No team has recovered from an 0-5 start to reach the playoffs, but the 49ers would have made it if they had defeated the Rams and won again next Sunday. If that had happened, San Francisco would have won the tiebreaker over Seattle and St. Louis to win the division and become the first team with a losing record in a nonstrike season to make the playoffs.

“You know what, I’ll put it this way: a personal failure. I’m the head coach of this team and obviously wanted us to do better, felt that we could do better,” Singletary said after Sunday’s loss. “There are some obvious questions that I hoped would be answered as the season went on, and obviously were not answered. When that happens, you end up out of the playoffs.

“I take full responsibility for every unanswered question.”

Singletary, who first took over as coach on an interim basis in October 2008 and soon declared “I want winners!” had two years remaining on his contract. York — son of owner John York — seems ready for major change around the Niners despite having to pay Singletary, a Hall of Fame linebacker during his playing days for the Chicago Bears.

“Money is no object,” Jed York said in St. Louis. “I mean, our object is to win the Super Bowl, year in and year out be there and compete for Super Bowls. We’re going to make sure we get this right.”

Initially, Singletary seemed to be the man to do it, with his way of ripping into a player one minute then finding a way to turn it into a positive.

During his debut in place of Nolan — a 34-13 loss to the Seahawks on Oct. 26, 2008 — Singletary pulled down his pants in the locker room at halftime to make a point, benched struggling quarterback J.T. O’Sullivan in favor of Shaun Hill, and sent now-Pro Bowler and captain tight endVernon Davis to the showers early for what he deemed inappropriate behavior following a personal foul penalty. Afterward, Singletary called out his team with the now infamous “I want winners” speech.

“I’d rather play with 10 people and just get penalized all the way until we have to do something else rather than play with 11 when I know that right now that person is not sold out to be a part of this team,” Singletary said. “It is more about them than it is about the team. Cannot play with them, cannot win with them, cannot coach with them. Can’t do it. I want winners. I want people that want to win.”

This year, Singletary fired offensive coordinator Jimmy Raye after Week 3, then lost secondary coach and special assistant Johnnie Lynn when he resigned for personal reasons earlier this month.

Singletary switched quarterbacks three different times, starting with Alex Smith, going to Troy Smith for five games even after Alex Smith’s hurt nonthrowing shoulder had healed, then back to Alex Smith for two games before Troy Smith started Sunday — only to give way to Alex Smith in the fourth quarter after Troy Smith had a heated exchange with Singletary.

“I’m not worried about individual things like that. What bothers me is we come in here, this is a playoff-caliber game, and we didn’t get it done,” York said. “And that’s the bottom line.”

York said he plans to hire a general manager and will open a search to fill the job. Since former GM Scot McCloughan departed last March — and ended up with Seattle — in what York called a “mutual parting,” San Francisco’s football operations have been run by vice president of player personnel Trent Baalke. He was responsible for selecting two offensive linemen with the team’s first-round draft picks in April, and both Anthony Davis and Mike Iupati are starters on the Niners’ revamped offensive line.

York was asked whether a new general manager would help in a potential coaching search.

“We’ll have a general manager, and as we go forward, that will be something that the general manager and I discuss together,” York said after the game.

Finding a quarterback will be another priority. Alex Smith most certainly will be gone after this season once the 2005 No. 1 overall pick’s contract expires.

Information from ESPN.com’s Mike Sando and The Associated Press was used in this report.