Vogelbach was optioned to Triple-A Tacoma on Thursday, Shannon Drayer of MyNorthwest.com reports.
This comes as a bit of a surprise, as Vogelbach and Danny Valencia were expected to split time at first base to open the season. The 24-year-old struggled this spring, however, slashing just .228/.313/.333 with 19 strikeouts in 57 at-bats. He also went just 1-for-12 with six strikeouts in his major league debut last season, so it appears the Mariners believe he could use some work before making the full-time jump.