Toronto's shortstop has experienced similar discomfort several times this season, but it wasn't until he aggravated the group of muscles on Monday night against the Red Sox that it became severe enough to force him to miss a game.
The injury is not considered serious, but Toronto decided to err on the side of caution for at least one more game.
"I'm able to play today," McDonald said. "But with the off-day tomorrow, it's just kind of wise to go easy today and get ready for Friday."
The hip flexor is a group of muscles that move the hip forward when running or walking. As a result, McDonald is able to swing the bat and play shortstop with relative ease, but is unable to run the bases without experiencing a lot of pain.
The injury comes at a very inopportune time for the 32-year-old. McDonald would be leading the American League with a .986 fielding percentage, but he hasn't appeared in enough games to qualify for first place. In order to take over the official lead, McDonald would need to appear in 108 games this season -- which means he has to play for at least half an inning in all of Toronto's final 11 contests.
Toronto manager John Gibbons hinted before Wednesday's series finale against Boston, it's likely McDonald would be brought in as a late-inning defensive replacement to keep him on pace to achieve that goal.
McDonald isn't the type of player who spends a lot of time pouring over individual statistics, but even he admits it's a milestone he'd like to reach because it would show how far he's come this season.
"It means a lot, just because this is the most amount of games I've played in a season," McDonald said. "And the fact that I've been relatively injury-free all season long. Missing yesterday's game was hard enough, and to not play again today, it's disappointing because I'm finally getting the opportunity to play more and I want to take advantage of it."
McDonald's career seemed destined to become a lifetime bench player until his breakout season with the Jays this season. He became a fan favorite by making highlight reel plays at shortstop the norm.
This is the first season McDonald has had a chance to play in enough games to capture the fielding title, but after signing a two-year, $3.8 million contract extension with Toronto, he's finally found a home and hopes he continues making an impact with his glove.
"I do it in a different way," McDonald said. "I'm not doing it as much offensively as I feel I do it defensively. But when you feel like you're contributing, you want to be out there everyday because you start building a trust with the guys around you, and you want to be out there with them."
Sticking with the status quo: Gibbons announced on Wednesday afternoon that he will not use Thursday's off-day to skip over anyone in the rotation and instead will use the time to give all of his starters an extra day of rest.
Right-hander Shaun Marcum, who is just 2-2 with a 7.94 ERA over his last six outings, had been considered one of the main options to receive an extra couple of days off. Toronto decided against that, though, after Dustin McGowan and A.J. Burnett threw a combined 17 2/3 innings over the past two nights.
"We were going tweak a little bit, but this way it gives everybody that extra day," Gibbons said. "We were possibly going to give Marcum an extra day but we decided [not to]."
Burnett rolling along: On Tuesday night, Burnett struck out 11 Red Sox batters and came within one out of recording his third complete game of the season. It marked the fifth time this season he's reached 10 or more strikeouts in a game and the 16th time he's done it in his career.
Since returning from a sore right shoulder on Aug. 12, Burnett is 4-1 while striking out 57 batters in 59 1/3 innings. Over that span of eight starts, Burnett leads the AL with a 1.97 ERA and opposition hitting average with .167.
Stairs moving on up: Toronto's Matt Stairs passed Terry Puhl for second all-time among Canadians with 1,532 games played. Stairs, a native of New Brunswick, already ranks No. 1 among active Canadian-born players with 239 career home runs.
Coming up: Roy Halladay (15-7, 3.82 ERA) is scheduled to take the mound for Toronto when the Blue Jays open a four-game series against the Yankees at 7:05 p.m. ET on Friday night at Rogers Centre. New York will counter with right-hander Chien-Ming Wang (18-7, 3.82 ERA).
Gregor Chisholm is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.