Jo-Lonn Dunbar has been suspended without pay for the first four games of the 2013 season for violating the NFL policy on performance-enhancing substances, the league announced Wednesday.
NFL Network's Michelle Beisner talked to a Rams source who said Dunbar's failed test was not a result of PED use.
"I just want to say that I did not take a performance-enhancing drug," Dunbar said, via The Associated Press. "I mistakenly took something that prompted a failed drug test."
"I sincerely apologize to my teammates (and) the organization," Dunbar added. "I am deeply saddened by this. But I plan to serve my four-game suspension and get back to playing football as soon as possible."
Dunbar was the 15th-best 4-3 outside linebacker last season, according to ProFootballFocus.com. It will be up to Witherspoon to replace Dunbar's impact, specifically against the run.