Pollock was making his first start since straining his left hamstring last week in a 9-2 loss to the Los Angeles Angels.
In the second inning Friday, Pollock singled in the game's first run but aggravated his hamstring injury when he took third base on Austin Barnes' RBI double. Pollock was removed for a pinch-runner.
"He felt it grab, so kind of right now, with where we're at, I assume it's gonna be an IL and we'll probably have a move tomorrow," Roberts said.
Pollock is batting .277 with four home runs and 17 RBIs in 32 games.