After taking the 10 days to rest and possibly rehab, Tanaka could take his final turn of the regular season, which could be largely contingent on whether the Yankees are still alive for a playoff berth.
Tanaka, who is 14-4 and leads the American League with a 3.08 ERA, complained of a little soreness in his right forearm after Wednesday's start against the Tampa Bay Rays. An MRI revealed, in Girardi's words, "a slight, slight, slight" strain in his flexor mass in the forearm.
Girardi, saying he didn't want to alarm anyone that it was a serious injury, stressed the location of the strain is not near Tanaka's elbow and instead is closer to his wrist. He also said specialists told him that it's unrelated to the ulnar collateral ligament tear that Tanaka suffered in his first year with the Yankees in 2014.
"From what we've been told it has nothing to do with the UCL ligament," pitching coach Larry Rothschild said.
Added Girardi: "I feel like this is just a little nick."
Girardi does not know who will start in Tanaka's place in Toronto on Monday. He mentioned Luis Severino as a possibility but said Severino will still be used out of the bullpen this weekend, which could eliminate him as an option.
Tanaka won Wednesday but gave up four home runs in his six innings and did not have an effective slider or cutter. If he is cleared to pitch going forward, he will go through his normal routine over the next five days, opening up the possibility that he could start the final weekend of the season against the Baltimore Orioles.
"I'm not worried at all," said Tanaka, who is a Cy Young Award contender. "I should be able to come back strong so I'm not really worried about anything."
On the season, Tanaka has thrown 199 innings. He has not reached 200 innings in any of his three seasons in the major leagues.
He missed two months of the 2014 season because of a small tear in the ulnar collateral ligament. He chose not to have surgery. In 2015, he went on the DL with a wrist and forearm injury and a hamstring issue. He had been injury-free in 2016.