The Reds reassigned Mathias on Wednesday.
Mathias had been vying for a utility gig on the Reds' Opening Day roster but didn't make a hard charge for a spot, as he went 0-for-5 in Cactus League play before being sent to minor-league camp in the latest round of cuts. If Mathias sticks around in the organization through the start of the minor-league season, he'll report to Triple-A Louisville.