ST. PETERSBURG, Fla. — New York Yankees ace Masahiro Tanaka will miss his scheduled start Monday at Toronto because of what manager Joe Girardi called a slight lower right forearm strain.

Girardi announced Tanaka's injury before Thursday nigh's game at Tampa Bay. He said Tanaka won't throw for five days but could start again before the regular season is scheduled to end Oct. 2.

"I feel like this is just a little nick," Girardi said. "I'm not going to make too much out of this. I don't think this is a huge thing. "

Tanaka had an MRI exam Thursday, one day after he gained up his 14th win despite allowing four homers in the third inning of a 11-5 win over the Rays.

"I should be able to come back strong," Tanaka said through a translator. "I'm not worried about anything. I look forward to coming back this season. I'm very confident that I should be able to get back soon."

Tanaka, who has won seven straight decisions, is 14-4 with an AL-leading 3.07 ERA.

"It's not the guy you want out, for sure," Girardi said.

New York started Thursday 2 1/2 games behind Baltimore for the second AL wild-card spot.

"I'm disappointed," Tanaka said. "We're making a push to make the playoffs."

Tanaka missed five weeks last season with right wrist tendinitis and a strained right forearm. In 2014 he was sidelined for 2 1/2 months due to a right elbow injury.