The Toronto Blue Jays keep finding new ways to injure themselves.
Pillar told reporters he suffered the injury while sneezing.
The Blue Jays don't appear too concerned regarding the injury to Pillar, as he's expected to be ready for Opening Day - good news for an already thin outfield.
Pillar played with the injury during Saturday's game but went for treatment after he was removed.
The 26-year-old, who is expected to compete for the starting left field job, hit .267/.295/.397 with two home runs and nine doubles in 53 games last season.