The Rams waived the 24-year-old Watkins last week. Per the St. Louis Post-Dispatch, Watkins was overweight upon reporting to training camp.
A second-year pro from South Carolina, Watkins — who’s listed at 6-foot-3 and 338 pounds on NFL.com — figures to contend for a reserve role with Kansas City. An ankle injury cut short his rookie campaign in St. Louis.
Watkins will miss the first game of the 2013 season for violating the NFL’s substance-abuse policy, the league announced in May.