Bautista left Monday night's 6-3 loss to the New York Yankees in the eighth inning because of a wrist injury.
"We've been fortunate as far as our everyday lineup is concerned," Blue Jays manager John Farrell said. "As far as injuries, we've been relatively injury-free. This is the first one and it's a big blow."
Bautista injured his left wrist on a swing in the eighth. He hit a long foul ball against David Robertson and immediately grabbed his wrist, dropping into a crouch outside the batter's box.
He walked off the field, gently supporting the wrist with his right hand after being attended to by several Toronto staff members.
After the game, the Blue Jays said Bautista did not break a bone. But he has a tendon injury and will have an MRI on Tuesday to determine the severity.
"He didn't say exactly when" he hurt the wrist, Farrell said. "But through the course of completing the swing he felt a little bit of a popping sensation."
Farrell said the Blue Jays will wait to make a roster move until they have a better idea how long the two-time defending AL home run champ will be out.
"There will be a follow-up transaction tomorrow," Farrell said. "Certainly, Jose's not going to be ready to go tomorrow."
Bautista tweeted a message about an hour after the game: "Thanks everyone for your concerns, XRAY negative and further testing tomorrow. (hash)FingersCrossed and wish me luck!"
Bautista is tied for second in the majors with 27 homers and his teammates know how valuable the fearsome All-Star is to their lineup.
"If it's for long term, it's devastating," reliever Jason Frasor said. "Yeah, I guess we'll wait and see."
The Blue Jays had already gotten bad news about their bullpen in the last couple of days. The team learned Sunday that closer Sergio Santos — out since mid-April — will have season-ending shoulder surgery. Then on Monday, left-hander Luis Perez scheduled reconstructive elbow surgery for Tuesday.
Overall, Toronto has six pitchers on the 60-day DL.
Raul Ibanez hit a tiebreaking grand slam with two outs in the eighth inning off Frasor. Ibanez connected on a 3-1 pitch for a no-doubt drive into the first row of the second deck in right field to snap a 2-all tie.
It was Frasor's third appearance in four games since the All-Star break, including an inning on Sunday.
"We've obviously put Frasor quite a bit. He gets into a little bit of an extended inning," Farrell said. "The grand slam to Ibanez was as much the overall usage."
The majors' two best power-hitting teams had padded their homer totals earlier — with Yankee Stadium specials. Both Russell Martin, in the second inning, and Adam Lind, in the fourth, hit line drives into the first row in right field.
"That short porch over there, it's been nice to me," Martin said.
Alex Rodriguez and Robinson Cano hit one-out singles in the eighth off Aaron Loup (0-1), recalled from the minors on Friday. Frasor came on and hit Mark Teixeira in the foot with a pitch. Teixeira tried to fake that he jumped out of the way because the ball bounced into the stands and A-Rod would have scored. Rodriguez had advanced to second on a passed ball before Cano's hit and was on third.
Ibanez then hit his 10th career slam.
Robertson (1-3) pitched a scoreless eighth for the win.
Cody Eppley put two runners on with one out in the ninth. The Blue Jays scored an unearned run when left fielder Dewayne Wise, a defensive replacement, misplayed J.P. Arencibia's single off Rafael Soriano, who finished for his 23rd save.
Fans hoping to see an offensive outburst from homer-happy clubs were foiled by the wild but effective outings of Henderson Alvarez and Phil Hughes.
Alvarez walked a career-high four in six innings. Hughes issued three free passes in seven innings, and each starter went over 100 pitches.
"He feels like, in the first couple innings, he was dropping his elbow down and he was always just taking off," Alvarez's translator said. "He was up in the zone. He found out and he made a little adjustment on that. He was getting on top of the ball. He was getting more strikes, more swings."
Hughes was hurt by a one-out walk to Bautista in the sixth. He scored from first on Edwin Encarnacion's double that tied it 2-all.
"Certainly wasn't a bad outing," Hughes said. "If this is the low end for the second half, that will be great."
Cano extended his hitting streak to a career-high 19 games with an RBI double past a diving Bautista in right field in the third after Rodriguez lined a two-base hit to left-centre to make it 2-0.
Lind's homer to right in the fourth made it 2-1 and was the 20th of the season off Hughes, but only the first in four games.
Rajai Davis snapped an 0-for-25 slump with a one-out double in the seventh.
NOTES: Yankees LHP CC Sabathia (groin strain) makes his first start since June 24 on Tuesday. He faces lefty Brett Cecil. ... The division rivals have 15 meetings remaining this season. Toronto swept a two-game series in May.Suggest a correction