Isringhausen played catch on flat ground Tuesday and pronounced himself fit after taking what he said was “4-5 days off” because of inflammation in his elbow. The Mets had indicated Monday that Isringhausen was shut down for one day, but the pitcher said he took off more time, and his elbow was helped by taking anti-inflammatory medicine.

Isringhausen said he will throw a bullpen session Wednesday, have a day off and then resume pitching every other day as he tries to make the team as a reliever. Manager Terry Collins said he hoped to get Isringhausen into a game Wednesday, but then said he would discuss the pitcher’s schedule with Warthen.

– Anthony McCarron, N.Y. Daily News.

Look: I want Jason Isringhausen to make the Mets’ Opening Day roster. Isringhausen, with all the hope and hype surrounding him, played a vital role in the summer of 1995, one of my favorite years of Mets fandom. His return to the team would make for a great story, plus he has been an excellent reliever for much of his career. If he could pull it all together for one more season, he would be a very valuable cog in the Mets’ bullpen.

But the thing about Izzy, heck, the thing about most 38-year-old pitchers — not just the ones with Izzy’s lengthy medical history who haven’t thrown more than eight Major League innings during the Obama administration —  is there’s a pretty good chance he falls victim to injury at any time. This four-to-five day shutdown is not a big deal in Spring Training because Grapefruit League games are meaningless. But how often will Isringhausen need to be shut down for four to five days during the regular season?

Who knows? He says he feels good, apparently. We will know more after he throws a bullpen session today.

If Isringhausen makes the Major League roster, it will come at the expense of one of Pedro Beato, Manny Acosta and Pat Misch. Beato is a Rule 5 pick who would have to be returned to the Orioles, Acosta and Misch are out of options and would have to clear waivers to be sent to Triple-A. Though none of those relievers has anything like Izzy’s resume, they’re all more likely than Isringhausen to stay healthy for a full season, or, for that matter, a full month.

The Mets’ front office is, presumably, working with more information than I am. They should have a better sense of the severity of Isringhausen’s elbow inflammation, the potential of Beato, Acosta and Misch to help the club over a full season, and the chances that Acosta and Misch would clear waivers.

I guess the question is: Is Isringhausen, at 38 and basically four seasons removed from being an effective Major League reliever, going to hold up long enough and be so much better than Acosta (or pick any of the three) that it’s worth losing Acosta?

Maybe. Acosta and Misch are known quantities, and neither is likely to go all Cliff Lee on the National League in 2011. But they’re both decent enough to contribute to a big-league bullpen, and if Isringhausen’s not healthy he won’t be.