Brett Anderson walked off the mound with the baseball in his left hand and flung it toward the ground. It was a frustratingly abrupt end to his role in the Brewers’ biggest game of the year.

Anderson, who began the season on the 10-day injured list with a blister on his left index finger, was forced to exit with the same problem after a second Cardinals runner reached to begin the third inning of Milwaukee’s regular-season finale at Busch Stadium on Sunday. When the Brewers managed to back into the playoffs despite a 5-2 loss, Anderson’s availability for the Wild Card Series against the Dodgers was not immediately clear.

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“He was doing good. It’s the same issue he had at the start of the season, but it hasn’t been an issue [since then], really,” manager Craig Counsell said. “Maybe it was the warm day and the humidity that caused it. But it just popped up.”

Freddy Peralta took over in emergency relief with runners at the corners and nobody out in what was a scoreless game. Peralta just returned to the team on Saturday from paternity leave, and was pitching for the first time in exactly one week when the Cardinals touched him for four runs in the inning and a 4-0 lead.

Anderson got help from his outfielders to navigate through the first two innings, with Avisaíl García crashing into the center-field wall for an impressive catch in the second.

But the lefty found trouble in the third, when Harrison Bader led off with a triple and No. 9 hitter Tyler O’Neill walked on nine pitches. It was after that plate appearance that Counsell and head athletic trainer Scott Barringer visited the mound and examined Anderson’s left index finger. After exiting the game, Anderson remained in the dugout instead of heading to the training room, a sign that he was not sidelined by a serious injury.

Signed to a one-year, $5 million contract last winter, Anderson ends the regular season with a 4.21 ERA in 47 innings over 10 starts for the Brewers.

The Brewers have only one set starter for their best-of-three series against the Dodgers, Brandon Woodruff, and he’s lined up to start Game 2 on Thursday if he remains on regular rest. Anderson is lined up for a potential Game 3, if the blister permits.

“We'll figure out how we're going to line everything up over the next day or so, and we'll go from there,” Brewers president of baseball operations David Stearns said.