Zylstra reverted to the Lions' practice squad Monday, per the NFL's transaction log.
Zylstra was elevated to the active roster prior to Sunday's Week 9 win over Green Bay but didn't log any offensive snaps. He did tally five snaps on special teams and returned one kick for 19 yards. Zylstra was also active in Week 7 but didn't see any offensive snaps in that game, either.