02:50 PM ET 04.16 | Cal wide receiver Keenan Allen was red-flagged for a drug test at the 2013 NFL Combine and forced to take another test this month. As of yet, there has been no indication why his initial test was red-flagged, and the results of Allen's most recent test are unknown. Allen's agent denied that his client failed any drug test, saying that Allen's recent retest concerned his knee and ankle injuries and not the drug test in Indianapolis. Allen has spent the offseason battling back from a troublesome knee injury that held him out of workouts during the combine and Cal's pro day. He performed well at a private workout last week, though it appeared that he was still dealing with lingering issues from the injury he suffered in October. Allen's 40-yard dash was in the 4.7-range.