Tellez will undergo an MRI on his right knee Wednesday, Arden Zwelling of Sportsnet.ca reports.
The 25-year-old began experiencing knee discomfort after stepping on a soft spot around the on-field bullpen, and the MRI will reveal the specifics of the injury. Tellez won't have a return timeline until the MRI results come back, but it wouldn't be surprising to see him receive Wednesday off regardless of the diagnosis.