Cal WR Keenan Allen will not participate in combine drills due to persistent knee injury

For the third time in the last week, it's been revealed that a potential first-round prospect will not work out at the scouting combine this week because of an injury. First, USC quarterback Matt Barkley said that he will wait until his pro day to throw as he recovers from a shoulder injury. Then, Alabama running back Eddie Lacy injured his hamstring while working out. Now, there's a third.

Cal receiver Keenan Allen, projected by many to be the best at his position in this draft class, will skip the drills at the combine in Indianapolis this week because of swelling in his left knee. Allen suffered a grade 2 PCL sprain in that knee in late November when Cal was playing Utah, and it ended his season.

[Also: Quarterbacks won’t star at NFL combine or draft]

According to CBS Sports' Bruce Feldman, who spoke with Allen's agent, Allen experienced swelling while training for the combine, got an MRI, and went to see noted surgeon Dr. James Andrews. Dr. Andrews diagnosed the Grade 2 sprain, and told Allen that surgery would not be needed. However, the kibosh has been put on Allen's ability to do his thing in Lucas Oil Stadium. Instead, Allen will work out for teams at two pro days -- Cal's standard pro day on March 14, where he's only expected to run routes, and a separate workout in April, where he'll run the 40 and do other speed and agility drills.

That will be an important day for Allen, and few players would have benefitted more from a great speed showing at the combine. Allen, who caught 205 passes for 2,570 yards and 17 touchdowns in three collegiate seasons despite the highly questionable nature of his school's passing game, is a deceptively fast player who's on-field speed will generally exceed his blast on a track. Fortunately, he does have a high-quality body of work to offset any concerns.

"I think with Keenan Allen, it's one word: speed," Mike Mayock of the NFL Network said in a recent media conference call when asked what Allen needed to prove at the combine. "That is the only question scouts have on him. It's hard to view him on tape with the way they throw the football. So what is it? If he's a 4.4 guy, bang the table, he's a top 25 pick. If he runs 4.55, 4.58, there are going to be a lot of questions about him.

"And off tape, if you like him, he's an Anquan Boldin‑type guy. If you don't like him, you're going to say he's speed deficient. So if he runs fast at the Combine, that is one of those positions where speed at the Combine means something, and he can really ‑‑ if he runs in that 4.4 to 4.5 range, 4.48 even, I think he's definitely a first‑round pick."

With all due respect to Mr. Mayock, who's one of the best draft analysts in the business, I think Allen is sneakier-fast than people give him credit for. But we'll have to wait a while to confirm that.

This news will likely increase interest in two other receivers -- Tennessee's Cordarrelle Patterson, and West Vurginia's Tavon Austin, both of whom could see their names called in the first round.

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