Unless I am mistaken, Jim Tomsula kinda sorta fired himself Monday.

Tomsula did not mean to do it, of course. But at his Monday media session, the 49ers head coach faced a question about how he and his staff are doing. He replied by basically admitting that the scoreboard (Detroit 32-17 in the latest delightful installment) does not work in their favor.

“We’re in a performance-based business,” Tomsula said. “We’ve got four wins, man. It’s volatile. I understand that, everybody understands that. When you’re a coach, the minute you sign the contract, boom, clock starts.”

Right. And it would seem that the clock is ticking down to Tomsula’s final moments at the podium.

It’s not as if the earnest Jimmy T even did much to argue with that premise Monday. Four times during his presser, Tomsula said there was “no excuse” for the seven neutral zone penalties by the 49ers defensive unit in Sunday’s game. He called the performance “no good.” Tomsula said that he could not “sit up here and defend it any way,” even though he was standing and not sitting.

What else? Tomsula also admitted that the 49ers’ sloppy tackling issues are not “nailed down” and that his staff “obviously doesn’t have the right answers yet” for that problem.

And there was this: I asked why Tomsula’s team, which began December with an uplifting overtime victory in Chicago, could not build on that result and what he might have done as a coach to make things go better over the past three weeks.

In response, Tomsula referenced the loss in Cleveland, which he acknowledged was “no good” and a “big step down.” Then, after he talked about how he still saw some good signs of the coaches and younger players starting to “gel,” he answered my question.

“What could I have done?” Tomsula said. “Probably, in Cleveland I put a lot of emphasis on starting fast in terms of throwing the ball, getting it down the field and things like that. And that’s just not how we’re built right now. So, that’s a Jimbo.”

He did not go on to precisely define what a “Jimbo” is. But my presumption is that it was a personal mess-up. Future historians may use the word to describe the entire 2015 season.

So to review: Tomsula said there was no excuse for the 49ers’ defensive “Jimbos” on Sunday. He said his staff can find no answers for the missed tackles. Also, he likely messed up the game plan in Cleveland himself by proposing that the 49ers offense try to do something it did not have the personnel to do.

To paraphrase a certain 49ers general manager, somewhere in there I think Tomsula said that he couldn’t give us much evidence that he should return in 2016.

Although just for the record, Tomsula said he had not discussed his job situation with the front office and stated: “I’m going to coach until somebody tells me I’m not.”

Count me among those who believe the 49ers will tell him he’s not. They almost have no choice.

I know, I know. Common wisdom says that owner Jed York and G.M. Trent Baalke will retain Tomsula because A) they don’t want to admit they were wrong in hiring him and B) they believe he had an impossible task because of last season’s key retirements and this season’s key injuries.

I am of the exact opposite view. The 49ers are in a discombobulated and dreadful state. York does not need airplane banners to tell him this. He must make many tough and radical decisions to get the franchise back on any sort of playoff contending path. He may or may not make those tough moves. But the easiest decision and simplest move is always to change head coaches. So that’s the first thing the 49ers will do.

Tomsula has indeed endured some unfortunate breaks. And he was inheriting an 8-8 team, not a division champion. Another .500 season would have been understandable and maybe even acceptable. But the recent losses to Cleveland and Detroit, two beatable teams that have had their own issues, were … well, no good and not excusable. They were Jimbos. After Tomsula is dismissed, who knows? Everything should be on the table. That includes Baalke’s position and the entire front office structure. York may only be willing to go so far. But he once fired Mike Singletary near the end of a six-win season — two more than Tomsula has earned so far — and then made a bold move by hiring Jim Harbaugh. Don’t automatically assume something like that can’t happen again.

The notion that no meaningful candidates will be interested in the position is also a false one. For instance, I have good information that Mike Holmgren, who coached both the Green Bay Packers and Seattle Seahawks to the Super Bowl, is interested in talking about the job. Holmgren has been out of the game since 2012. But as a San Francisco native and former 49ers offensive coordinator, he has an affection for the franchise.

None of that may lead to anything. Holmgren is likely to make demands about personnel matters that the 49ers are reluctant to meet. But why not at least kick the tires on Holmgren’s comeback vehicle? He is 67 years old. But here are four other current NFL head coaches in their 60’s: Tom Coughlin, Pete Carroll, Bill Belichick and Bruce Arians. Three of the four have won Super Bowls. The fourth may win the next one. Plus, if Holmgren is interested in the gig, others surely would be under the right conditions.

Meanwhile, Tomsula does have one more game to coach this season, Sunday against St. Louis at Levi’s Stadium. It would be nice to see him go out without a Jimbo. But I can’t see it making a difference in whether there’s a new 49ers coach in 2016. Tomsula himself keeps making the best case for it.

Read Mark Purdy’s blog at blogs.mercurynews.com/purdy. Contact him at mpurdy@mercurynews.com. Follow him on Twitter at twitter.com/MercPurdy.