CINCINNATI -- Jose Bautista aggravated a left leg injury during Sunday afternoon's 4-3 loss to the Reds, but the severity of it won't be known until he undergoes an MRI in Toronto.

Bautista had been bothered by some tightness in the back of his leg the past couple of days, but the discomfort became more severe in the series finale. He left the game shortly after reaching first base on a bunt attempt down the third-base line.

The 33-year-old is scheduled to undergo an MRI when the Blue Jays return home on Monday. Until then, he doesn't want to say whether there's a belief this could be a long-term issue or something that requires just a few days of rest.

"I don't feel too bad but I really want to see what the MRI says before I can answer a question like that," Bautista said. "I might not feel too bad, but the MRI might show some inflammation or irritation.

"I don't even know what it could show, and the fact that I could make it worse it might be better to sit out for a couple of days or so and let it calm down. The most important thing is seeing the MRI tomorrow, because I don't feel terrible but I know there's something going on."

Blue Jays manager John Gibbons initially said it was a hamstring issue, but Bautista declined to confirm that and instead stated, "it's an in-between area, just the back of the leg." That would seem to indicate the discomfort is located near the bottom of his hamstring, which could also involve the knee.

Everyone in the organization likely will be waiting on pins and needles for the results of the MRI because the Blue Jays can ill afford to lose Bautista for a significant period of time. The club is already without third baseman Brett Lawrie, who fractured his right index finger after getting hit by a pitch on Sunday and will be headed to the disabled list.

Left-handed reliever Brett Cecil is currently on the 15-day DL with a strained groin while Adam Lind remains hobbled because of a sore right foot and has been limited to pinch-hitting. Jose Reyes entered the game to take Bautista's spot in the lineup on Sunday, but he too has been dealing with an injury after fouling a ball off his left knee on Saturday.

The most significant injury of all, though, would be one to Bautista. The veteran right fielder is the heart and soul of the Blue Jays' lineup and is currently hitting .305 with 15 homers, 49 RBIs and a .959 OPS in 77 games.

"I had a little tightness in the area for the past couple of days but playing through it and today just got bad enough that I didn't want to risk serious injury," Bautista said. "Just a precaution to come out, take a precautionary MRI just to make sure there's nothing going on there. That's it, hopefully it's not too bad and hopefully I can get back into the lineup whenever."