The third baseman exited Toronto's game against Detroit during the third inning, marking the second time in six days that a troublesome heel forced Glaus to leave a contest prematurely. About the only certainty was that Glaus wouldn't be in the lineup on Friday.
"I don't know," said Gibbons when asked the extent of Glaus' injury. "He's banged up. We knew that going in. We'll just evaluate it and see where we're at tomorrow."
After grounding into a double play to end the first inning, Glaus labored down to first base and Gibbons decided that was enough. Infielder John McDonald, who took over at third base in the third inning, said it seemed obvious that Glaus needed to be removed.
"When he was running down the first-base line, he pulled up a little bit," McDonald said. "Immediately, Jason [Smith] and I went up and started to get loose. Either one of us were prepared to go in the game."
Initially, the Blue Jays announced that Glaus left the game for precautionary reasons due to soreness in his left heel, which has been bothering the infielder all week. Glaus was listed as day to day, but Gibbons wouldn't elaborate on how serious the injury might be.
"He won't be playing tomorrow," said Gibbons, who was unwilling to speculate about Glaus' status beyond Friday.
On Saturday, Glaus felt something in his heel as he ran out of the batter's box in the first inning against the Devil Rays. The 30-year-old third baseman remained in the game until Gibbons pulled him in the fifth. Afterward, the Jays said Glaus had aggravated his Achilles' tendon in his left foot.
Glaus returned to the starting lineup on Monday, when Gibbons said the 6-foot-5 slugger was dealing with a bone spur in his left heel -- an ailment related to the Achilles injury. Toronto's manager indicated that the injury wasn't serious at the time, but he said the club would continue to monitor Glaus in each game.
"Every now and then it flares up," Gibbons said Monday. "Sometimes when you jam your foot on the bases, it just jars it a little bit. There's a lot of body on top of that heel."
Gibbons added that Glaus dealt with the problem every so often last season, too. Still, the third baseman was able to appear in 153 games and recorded 38 home runs and 104 RBIs. In 2005, Glaus hit 37 homers in 149 games with Arizona despite playing with a strained tendon behind his left knee.
This season, Glaus is hitting .333 with two home runs and five RBIs in eight games. The Blue Jays know that losing Glaus, who hits fifth, would create a big hole in the lineup. Toronto also lacks a true backup at third base on its current roster.
"Hopefully, it's a minor thing and we can get it healthy and get him back in the lineup," Jays first baseman Lyle Overbay said.
Jordan Bastian is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.