ATLANTA — Upping the absentees to four of eight starting position players, the Mets put rightfielder Michael Conforto and second baseman Jeff McNeil on the injured list on Monday.

Conforto has a strained right hamstring. McNeil has a strained left hamstring. Both injuries occurred in the first inning on Sunday.

The Mets did not reveal the severity of the strains as they waited for opinions from more doctors regarding the MRIs. But manager Luis Rojas said the club is "doing a week-to-week approach," suggesting Conforto and McNeil will miss more than the minimum 10 days.

To take their roster spots, outfielders Khalil Lee and Johneshwy Fargas were called up from Triple-A Syracuse. Neithr had played in the majors until Monday.

The injury problems got even worse during the game, when righthander Taijuan Walker departed after three scoreless innings (33 pitches). The Mets said he had "left side tightness."

"Our identity right now has changed a little bit from a position player standpoint," Rojas said. "We have a couple guys that can run a little better, a couple guys that can put the ball in play at a different rate than the guys that we don’t have. We’ve got to find a way of scoring runs, and that’s kind of been my message to the guys since earlier [Monday]."

The Mets transferred Seth Lugo to the 60-day IL to clear a spot on the 40-man roster for the 26-year-old Fargas.

Conforto and McNeil join Brandon Nimmo and J.D. Davis, who are sidelined with finger injuries. Davis, set to begin a rehab assignment with Triple-A Syracuse on Tuesday, is closer to returning.

Altogether, the Mets’ injured list body count is 12 of 45 players on the 40-man roster (including five on the 60-day IL). That is more than one out of every four.

Righthander Taijuan Walker (left side tightness) and outfielder Kevin Pillar (hit in the face by a pitch) left the Mets’ 3-1 win over Atlanta early.

The other hurt Mets are Lugo, Jacob deGrom, Carlos Carrasco, Noah Syndergaard, Luis Guillorme, Albert Almora Jr., Dellin Betances and Jose Martinez.

"Very, very frustrating," a dispirited Conforto said of getting hurt at a time when so many teammates are out. "I feel like that's the only way I can put it. Just very frustrating."

Before feeling his hamstring grab as he ran to first base, Conforto had been managing various other minor issues, "just normal stuff that you deal with," he said. That included tightness in his lower back and hamstrings, plus a calf that was still not quite normal after an outfield collision with Kevin Pillar last week.

Conforto said he "felt like I had a good grip on all that stuff." Then the Mets visited the Rays, who play on artificial turf.

"The ground over there is a lot harder than it would be on grass," Conforto said. "I don't know exactly what it was that caused the injury, but I'm sure it didn't help."

Without McNeil, Jose Peraza started at second base again. That likely will be the norm until another infielder returns.

Without Conforto, Pillar moved to rightfield and Fargas got the start in centerfield, his major-league debut. He went 1-for-3 with an RBI double.

Fargas, who joined the Mets on a minor-league contract before the 2020 season, is the best defensive outfielder on the 26-man roster, Rojas said. He added that Fargas, who stole eight bases in eight games from Syracuse, has "elite" speed.

Lee, 22, is more of a prospect, combining some speed with some power. He, too, made his major-league debut, replacing Pillar in the seventh inning. He struck out in his only at-bat.

The Mets prefer Lee in the corner outfield spots because he has a "really good arm," Rojas said. They acquired him from the Royals in a three-team trade with the Red Sox in February.

"We’re going to be aggressive," Rojas said, "and we’re going to create situations for us to score runs."