LOS ANGELES -- The Mets’ rotation, already thin, absorbed another blow on Tuesday when the team placed Carlos Carrasco on the 15-day injured list due to right elbow inflammation.

Carrasco, who had been scheduled to start Friday in San Francisco, went 0-2 with an 8.56 ERA over his first three outings. His velocity was notably down in those games, and he walked as many batters (eight) as he struck out.

Although Carrasco submitted his best start last time out in Oakland -- allowing two runs in five innings -- he came away from it with abnormal soreness and swelling in his elbow, according to manager Buck Showalter. That prompted the Mets to monitor Carrasco and, eventually, fly him back to New York for an MRI. The team should know the results of that test by Wednesday.

“It’s been a challenge,” Showalter said.

Elbow issues are nothing new for Carrasco, who is 18 months removed from surgery to remove a bone fragment from the joint. Carrasco also skipped his final Grapefruit League start due to what Showalter called “elbow maintenance,” describing it as typical for Carrasco. To what extent Carrasco experienced continued discomfort into April is unclear.

In his absence, the Mets will need to dip further into their starting pitching depth, which was robust at the start of Spring Training but has since absorbed multiple hits. In addition to Carrasco, starters Justin Verlander (teres major strain) and José Quintana (recovery from rib surgery) are on the IL. Verlander is due back in May, Quintana not until July at the earliest. Their absences have forced the Mets to make David Peterson and Tylor Megill regular members of the rotation, where both have experienced success.

The Mets also pushed back Max Scherzer’s last start due to lingering back soreness; he’s due to return to the mound on Wednesday.

“I try to look on the positive side,” Showalter said. “I hope tonight and tomorrow go well.”

So who might replace Carrasco? Scherzer’s temporary replacement, José Butto, was optioned back to Triple-A Syracuse on Monday. The Mets could have recalled Butto when they placed Carrasco on the IL, but they instead opted for an extra reliever, Jeff Brigham. MLB rules now prohibit the Mets from recalling Butto within 10 days of his demotion, unless the team places someone else on the IL.

The most obvious candidate to come up from Syracuse is left-hander Joey Lucchesi, who is 2-0 with a 2.30 ERA in three starts with Syracuse. The team could also proceed with a bullpen game if it wants to push reliever Tommy Hunter, who is due back from the IL in the coming days, for multiple innings.