Campbell was placed on the 7-day injured list at Triple-A Worcester on Thursday with a left foot contusion, Chris Cotillo of MassLive.com reports.
While the injury seems relatively minor, there's a chance it will end Campbell's season given how little of the schedule is left. Campbell put up a .631 OPS with just two home runs through the end of June at Worcester this season, but he's slashed .320/.440/.524 with six long balls since July 1.