As soon as the 2012 NFL draft was over, Keenan Allen sat perched atop the wide receiver rankings for this year's draft.

He stayed there for much of the college season despite having a tough time in an anemic California defense. A knee injury kept him from finishing out the year, but it wasn't until draft season picked up that other receivers made a run on the consensus board.

Allen has something to prove heading into the draft. Is he still a first-round pick? Can teams overlook the negatives?

Before we get there, here are five things you should know about the receiver out of California.

Combine results courtesy of NFL.com. College stats courtesy of Sports-Reference.com.

Full Name: Keenan Alexander Allen

Birthday: April 27, 1992

Hometown: Greensboro, N.C.

School: California

Major: African-American studies

Year: Junior

Twitter: @KAAdeuce1 (unverified)

Keenan Allen is one of the draft's younger prospects, turning 21 during the draft.

Despite playing in a poor offense, Allen had a rather nice sophomore season. He caught nearly 100 passes in just 13 games, a phenomenal number.

His final season was, again, cut short by injury, but he managed to surpass his career high in total touchdowns.

Offense

Special Teams

Measurables

Height: 6'2"

Weight: 206 lbs.

Arm Length: 32.75"

Hand Size: 10"

Pro Day Results

40-yard dash: 4.71 seconds

The torn PCL Keenan Allen suffered in October lingered through much of draft season. 

He was unable to perform at the combine or California's pro day. It wasn't until recently that he was able to show anything, despite not being 100 percent recovered from his knee injury.

A poor 40-yard dash time has further put a damper on the receiver's draft stock, however.

Allen was involved in a bit of a recruiting brouhaha that led to his commitment to Cal.

Prior to that, Allen had verbally committed to Alabama, where he would have followed in Julio Jones' footsteps. Had Allen played college ball in Tuscaloosa, we might be talking about a top-five pick in the draft.

But half-brother Zach Maynard changed his tune when he decided to go to Cal instead of the University of Buffalo. That opened the door for Jeff Tedford to snag Allen alongside Maynard.

Keenan Allen has been the antithesis to Tavon Austin this draft season. His draft stock, at least among the masses, has fallen precipitously throughout. What does Twitter have to say?

#Cal WR Keenan Allen finally ran for scouts and clocked a 4.71. That along with health / durability questions could push him out of Round 1.

— Scott Wright (@DraftCountdown) April 9, 2013

Sorry to hear that Keenan Allen's knee will hold him out of combine drills. He's faster than some think and will have to wait to prove it.

— SC_DougFarrar (@SC_DougFarrar) February 20, 2013

Cal's Keenan Allen, projected as a top WR in upcoming draft, is nursing a sprained PCL that will prevent him from working out at combine.

— Adam Schefter (@AdamSchefter) February 20, 2013

Keenan Allen and C-Patterson are very different WRs, but if buzz is correct two teams are going to get two talented players in the 2nd.

— Josh Norris (@JoshNorris) April 10, 2013

If Keenan Allen really slips into the 35-40 range, teams should be lining up to trade up for him. He's as NFL-ready as any WR in this class.

— Chris Burke (@ChrisBurke_SI) April 9, 2013

Combine results courtesy of NFL.com. College stats courtesy of Sports-Reference.com.

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