Souza's hamstring strain is in the Grade 1 category, Mark Gonzales of the Chicago Tribune reports.

EDGE Analysis

Thankfully for Souza and the Cubs, the injury that sent the outfielder to the injured list Tuesday fit into the mildest category. It's not clear exactly when he's expected to return, however. Souza primarily filled a bench role to start the season, so his loss won't be a major one for Chicago.