MIAMI -- The week did not get off to a good start for former Boise State running back Jay Ajayi.

The Dolphins' leader in rushing yards from a year ago is being evaluated for a concussion after leaving practice early on Monday, according to

It was the first full-contact practice of the season for the Dolphins. Backup running back Kenyan Drake told Adam Beasley of the Miami Herald that Ajayi was "taking shots right and left" during practice.

Joe Schad of the Palm Beach Post noted one play in-particular where safety T.J. McDonald got the best of Ajayi.

Ajayi burst on to the scene in his second NFL season in 2016. He rushed for 1,272 yards, the fourth most in the NFL. He also led the NFL in missed tackles, according to Pro Football Focus.

Ajayi is expected to be the Dolphins starter at running back this season.