Motter was recalled from Triple-A Tacoma on Tuesday.
With Nelson Cruz (ankle) hitting the disabled list, the Mariners were in need of another bat. Motter will fill that void, though it's unlikely that he'll fill a regular role during his time in Seattle. The utility man demolished Triple-A pitching last season to the tune of a 1.067 OPS, but he failed to translate it to the big leagues, batting .198 in 258 at-bats.