Injured New York Mets pitcher Jason deGrom watches from the...

Injured New York Mets pitcher Jason deGrom watches from the dugout against the Washington Nationals on May 31, 2022. Credit: AP/Mary Altaffer

Jacob deGrom will take another tangible step toward returning when he begins a rehabilitation assignment Sunday night with Low-A St. Lucie, but the Mets’ public plan after that underscores the unfortunate reality: They just can’t be sure what will happen next.

That is true for any injured pitcher, but especially deGrom, who this week will hit one year since he most recently pitched in a major-league game. The stress reaction in his right shoulder blade is his most serious in a series of injuries the past couple of years. The Mets want to avoid a repeat of the healthy-until-he’s-not scenario that has played out repeatedly.

DeGrom is scheduled for about two innings and 25 pitches in this first outing.

“I’m going to take the start, see how he recovers, take the bullpen day, see how that feels, take the day after that for strength testing, see how that feels, make a call,” general manager Billy Eppler said Saturday. “We’ll get manual, clinical-type tests done so we can see what the strength looks like start to start, day to day. Then take Jake’s feedback and make an educated decision based on all of those inputs.”

In line with their deGrom norm, keeping the details of his recovery as much of a secret as possible, Mets officials declined to say how many minor-league starts they plan for him. But manager Buck Showalter acknowledged that “the rehab will take him to a mark that’s five innings or more.”

That raises an interesting possible target: the July 26-27 series against the Yankees at Citi Field. DeGrom will have time for four rehab appearances — a start of two innings, then three innings, then four, then five if he follows a standard buildup — and a couple of extra rest days mixed in before maybe making his season debut during the Subway Series.

Rehab assignments for pitchers have a maximum of 30 days. If he uses the whole clock, it would take him to Aug. 3.

Showalter reiterated that deGrom has reached every checkpoint exactly when the Mets’ medical staff expected he would. They never share that schedule, but all has been and is well, they say.

“If there is an adjustment to be made, [they’ll make it]. So far, we haven’t had to make an adjustment,” Showalter said. “I’ve been really impressed how that calendar they gave me two months ago has followed just about everything.”

McNeil’s maintenance

Jeff McNeil has “no pain, no problem” with his problematic legs, but he was out of the lineup anyway Saturday to protect them, Showalter said. That came a day after he served as the designated hitter, which came a day after the team’s day off.

McNeil, who Showalter compared to a baby horse, recently missed a week because of a right hamstring injury.

“It’s kind of like when the foal comes out newborn and the legs are getting under him a little bit. I think he’s going through that a little bit,” he said. “Like [Friday] running to third base. I was talking about it this morning. Nothing hurt or anything, but he just didn’t know how far to really let it fly. And he will. With each day, he’ll get more and more confident with it.”

Papa Peterson

David Peterson headed to Denver on Saturday for the birth of his first child, but the Mets didn’t officially put him on the paternity list because it comes with a three-day maximum. That technicality buys him an extra day or so away from the team, if needed.

“He’ll be back when he thinks it’s appropriate to come back. It’s he and his wife’s decision,” Showalter said. “We wish them well and hope everything — I don’t want to say comes out well, but hope the end result ends well. We’re hoping for good things for him and his family.”

The Mets have not named a starter for Peterson’s next turn in the rotation on Wednesday against the Reds.

Extra bases

Edwin Diaz was named the NL reliever of the month for June, MLB announced. He had a 0.93 ERA and 21 strikeouts (to one walk) in 9 2⁄3 innings .  .  . Trevor May (stress reaction in his right humerus) said his bullpen session Saturday, his first since getting hurt, went well .  .  . Showalter on vouching for the Mets’ several All-Star candidates: “I really like to support our players’ feelings.”