ESPN reported Tuesday that Allen was red-flagged for a drug test at the NFL scouting combine in Indianapolis and was ordered to undergo another test this month, league sources said. Allen's agent, J.T. Johnson, denied that his client had failed any drug test. One source said Allen had suspiciously high levels of water in his system.
However, a letter from the scouting combine said Allen had an April 6 meeting at Methodist Hospital to check his ankle, not to undergo another drug test.
Allen was dealing with knee issues at the combine that prevented him from working out in Indianapolis.
ESPN.com's Mel Kiper Jr. has Allen ranked fourth among prospective receivers and going 40th overall to the Tennessee Titans in his most recent mock draft.
Information from ESPN NFL Insider Adam Schefter was used in this report.