"It all depends on how it is tomorrow," Gallardo said. "It's stiff now, but hopefully it's nothing big."
Roenicke anticipates bumping Gallardo's next bullpen session -- scheduled for Thursday -- back one day as the manager said that the team will likely have a better idea of Gallardo's status then.
Gallardo sustained the injury when he tried to field a chopper off the bat of Julio Teheran in the top of the fourth. He appeared to roll his left ankle while changing directions to react to Teheran's grounder, and then landed awkwardly on the same ankle on the front slope of the mound after leaping to field the ball.
"I couldn't tell," Gallardo said of when the injury occurred. "I know I was just trying to change directions to try to get that ball and it just rolled me. I mean, it's not the first time it's happened. For some reason, it's always my left ankle."
Roenicke and Brewers trainers went out to the mound to check on Gallardo, who walked with a significant limp following the play. The right-hander threw a few warm-up pitches to test the leg before Milwaukee decided to pull him.
"He wanted to stay in the game," Roenicke said. "Our concern is you have a bad ankle and all of a sudden you land funny and you do something to your arm. It's not worth taking the chance on that to get a couple of extra innings out of him."
"I tried, I definitely tried, but it's my landing leg," Gallardo said. "The last thing you need to do is try to overcompensate."
The injury halted Gallardo's start at 3 1/3 innings -- his shortest outing since he lasted only 3 2/3 innings against the Padres on July 25, 2013. His early exit also ended a streak of 17 straight starts with at least 5 2/3 innings pitched.
Joe Morgan is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.