Clouds continue to gather over the NFL draft status of former Cal wide receiver Keenan Allen after ESPN.com reported Tuesday that his drug test at the combine was red-flagged.

Allen's agent insists the story is wrong.

"We have received no notification about anything abnormal to his test. No team has requested a retest. Nobody," said J.T. Johnson, adding that he first got wind of this when a reporter called him last Friday.

One thing is clear: Allen, once the consensus top prospect at his position, no longer is a sure thing to go in the draft's first round on April 25.

The ESPN report said Allen showed suspicious levels of water — suggesting he was trying to flush his system — and he was ordered to take another drug test. "It's news to me, news to Keenan," Johnson said.

Johnson, said his client did not fail a drug test and emailed this newspaper a document showing that Allen was asked to return for a combine recheck at Indianapolis on April 6 to undergo an examination of the ankle he broke more than a year ago.

Johnson said Allen's knee and ankle both got positive medical reports.

Jeffrey Foster, president of National Football Scouting, Inc., which runs the combine, confirmed players often are invited back for a recheck of injuries. He said he doesn't know anything about a drug retest being ordered.

"I can tell you we — the combine — did not order a retest of the drug tests for anybody, and we did not conduct any drug testing at the ReChecks," said Foster, noting individual teams can do their own testing of players.

Asked if Allen were available to be interviewed, his agent said, "He told me just wanted to relax and stay under the radar." His draft stock has plummeted since he injured his left knee in Cal's Oct. 27 game at Utah, then suffered a setback in January during workouts preparing for the combine. The knee injury required no surgery.

The latest report comes just one week after Allen turned in mediocre 40-yard dash times at a private workout for NFL scouts.

Draft expert Mike Mayock of the NFL Network said in a report after Allen's April 9 workout in North Carolina that he still considered Allen the third-best receiver prospect in the draft.

Mayock timed Allen at 4.71 and 4.75 seconds in the 40, but believes that doesn't reflect how fast he is when fully healthy.

"If you like him, he's Anquan Boldin. If you don't like him, he's speed-deficient," Mayock said last week. "So I don't really care what he runs in the 40. On tape to me, he's a 4.55 guy all day long." Mayock said many of the NFL scouts he talked with at Allen's workout agreed, adding that he projected Allen to be the third wideout taken in the draft, somewhere between No. 25 and 45.

At 6-2, 206 pounds, Allen gets high marks for his route-running and hands.

"He's quick and explosive off the ball," Mayock said. "Does he have that high-end burst right now? No. Will he ever be a 4.4 guy? No. I love the fact that this kid competes." Allen was projected as high as No. 5 overall on one NFL mock draft last fall. Then he sprained the posterior cruciate ligament in his left knee and missed Cal's final three games.

Two draft analysts with CBSSports.com early this week had Allen going 25th and 27th, respectively, but two others projected him as a second-round pick.

"There are some medical concerns and there are some speed concerns," Mayock said.

And now there may be one more concern. Players know they face drug testing at the combine, so a failed drug test calls into question a player's judgment.

Mike Adams, an offensive tackle from Ohio State, tested positive for marijuana at the 2012 combine and was told by the Pittsburgh Steelers that he was off their draft board. Then they took him anyway with the No. 56 overall pick.

Allen has no history of off-field incidents that suggest character issues.

"I believe in the kid," Mayock said last week.

We'll know a week from Thursday if NFL teams feel the same way.