Dunn (shoulder) threw a simulated game Friday, Shannon Drayer of 710 ESPN Seattle reports.

Dunn is expected to begin a rehab assignment soon, and Friday's throwing session marked the first time he faced live hitters since he was placed on the injured list in mid-June. The right-hander shouldn't need much time to build up his pitch count since the Mariners plan to use him as a reliever once he's cleared to return.