Miami on Tuesday released running back Jonas Gray and re-signed center Sam Brenner.
Gray was expendable after Ajayi’s strong debut in Sunday’s 33-17 loss to Buffalo.
Ajayi, who appeared in his first NFL regular-season game after spending the first eight weeks on the injured-reserved list, was a rare bright spot on Sunday.
While it was a small sample size, the Dolphins liked what they saw from Ajayi, who ran five times for 41 yards, an average of 8.2 yards per carry.
Interim coach Dan Campbell said he likes how Ajayi “puts his foot in the ground and he goes.”