Mathias was reassigned to minor-league camp Friday.
Mathias got to spend some time in big-league camp but was never a candidate to open the season on the major-league roster, as he's yet to reach Triple-A. He's spent the entirety of the last two seasons stuck at Double-A, and it remains to be seen whether his .232/.338/.370 line for Akron last season will be enough for him to start this season at the next level.