Cubs manager David Ross said Holloway suffered a moderate right oblique strain in Monday's 3-0 loss to the Diamondbacks, Jordan Bastian of MLB.com reports.
The right-hander, who is attending camp as a non-roster invitee, failed to retire a batter and was charged with two runs on two hits prior to departing. Ross didn't provide a timeline for Holloway, but given the nature of the injury, the right-hander is likely to miss enough Cactus League action to take him out of contention for a spot in the Cubs' Opening Day bullpen.