TORONTO — Clint Frazier said late Wednesday night that he wasn’t “too concerned” about his sore left oblique.

An MRI taken the next morning showed he had reason to be.

The rookie outfielder was placed on the 10-day disabled list with a strained oblique on Thursday and was replaced by outfielder Aaron Hicks, who had been on a rehab assignment.

The original plan was for Hicks, on the DL since June 26 with a right oblique strain, to return Friday, but that was before Frazier’s injury. “A day early is not going to make a big difference,” Joe Girardi said. Through seven innings Thursday night, Hicks was 0-for-5 Thursday night.

Frazier, who cooled off dramatically after a hot start, was a late scratch from Wednesday night’s game when Girardi saw him favoring his left oblique area. Frazier said Thursday that he had been feeling some discomfort there since Saturday in Cleveland.

Frazier, 22, has a .243/.274/.477 slash line, four homers and 17 RBIs in 28 games and is in a 5-for-33 slide. He doesn’t believe the injury will sideline him for long.

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“I know it’s probably best for me to be on the DL to give it some time so I don’t hurt it any worse,” he said. “It didn’t hurt enough to not be able to play, but it hurt enough for me to know every pitch that something was there.’’

Hicks was hitting .290 with a .913 OPS, 10 homers and 37 RBIs in 60 games when he went to the DL.

“I’m ready to go out there and battle and do what I can to help this team win,” he said. “Try and produce as many runs as I can.”

Return of Monty

Girardi said it is “a really good possibility” that Jordan Montgomery will take CC Sabathia’s start Sunday night against the Red Sox. Sabathia left Tuesday night’s start with soreness in his right knee, and though an MRI showed no damage, having the 37-year-old lefty start so soon after that would seem a stretch.

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“I want to see CC tomorrow before we make a decision,” Girardi said. “But my inkling is [no]; he came out of the game in a substantial amount of pain.”