Mostert, 25, wound up signing on with the Eagles as an undrafted free agent out of Purdue back in 2015. He had brief stints with the Dolphins, Ravens, Browns, Jets and Bears before signing on to the 49ers’ practice squad late last year.
Mostert managed to make the 49ers’ active roster coming out of the preseason this September.
In 2017, Mostert appeared in 11 games for the 49ers and rushed for 30 yards on six carries (2.7 YPC) and no touchdowns. He also totaled 83 kick return yards.