Mickey Callaway is still the Mets’ manager for many reasons. The most important, though, has nothing to do with his likability, wealth of pitching knowledge or even ownership’s distaste for eating around the $1.7 million he is owed through next year.

Callaway’s greatest defense is simply, if not him, who?

If your knee-jerk response is some form of “anyone would be better,” then let’s at least go through the exercise of what is available and plausible.

The first consideration is always inward. It was posited from Jim Riggleman’s offseason hiring as bench coach that he had two responsibilities: 1) Help make Callaway a better manager in 2019 than his 2018 debut and 2) replace him if responsibility No. 1 did not go well. But if the Mets wanted to do that you really get no greater open-door policy than being swept into humiliation by the Marlins.

Perhaps the Mets wanted to still give Callaway more time. But face it, if the Mets were inspired by elevating Riggleman it would have been him sitting at a Citi Field microphone Monday, not Callaway. And there is really no other obvious choice. Gary Disarcina was stripped of the bench coach role after last season. My colleague, Mike Puma, has mentioned how much the Mets like quality control coach Luis Rojas, but I just can’t see the organization elevating its 37-year-old quality control coach into this job in midseason.

So, now think about external alternatives. The rule is for any candidate to say he would never interview while someone is still in the managerial chair. But in the real world there are attempts to back channel and be discrete. Nevertheless, what can’t happen is a full interview process; long sitdowns with multiple members of the organization covering lots of areas — and then call backs for multiple rounds. Not in the middle of a season.

Brodie Van Wagenen may only get one shot to hire his own manager on a multi-year contract. He values process and information. So, is he really going to hire a long-term manager in May without being able to go through the full search, vetting and interview process? In the offseason Van Wagenen could have Rojas sell himself and bring in, say, MLB Network’s Mark DeRosa, who perhaps was Callaway’s runner-up after the 2017 season when Sandy Alderson was running the interviews, or see if his pal, Astros manager A.J. Hinch, might recommend Houston bench coach Joe Espada plus more.

The only possibilities I see that could throw a curve is if Buck Showalter, 63 on Thursday, or Dusty Baker, 70 next month, would accept an interim tag with the promise of full consideration after the season. Both could say they have accomplished too much to have to audition. Understood. No way I could imagine, say, Joe Girardi considering such conditions.

This would have to be about desperation at a time when most organizations have turned strongly away from the older, accomplished manager to hire younger options, who are more analytically savvy and more open to input from various facets of the organization. Baker and Showalter might never get a multi-year chance again despite having each managed in four separate places and combined for 14 playoff appearances. The Mets, if they were interested, could represent a last best chance for either man to chase that elusive championship (only Gene Mauch has managed more games than Baker or Showalter without winning a World Series).

I communicated with both on Monday before Van Wagenen’s tepid “foreseeable future” endorsement of Callaway. Baker and Showalter indicated they would still like to manage, but that the Mets had not been in contact.

So you see how the ranks of “anyone would be better” thins when faced with what is available, plausible and sensible. Still, Callaway should hardly feel secure.

He did not have strong backing entering this year, underscoring that if a change was going to be made it should have been made last offseason. Nothing has changed. Callaway is not roundly loved in the job by his players or his bosses.

But the candidate list in late May and the ability to do a thorough search is not great. This is why Callaway survived the Marlin massacre as much as any unflinching support. His best defense — unless the team begins to win a heck of a lot more often — is if not him, who?