BATON ROUGE, La. -- The race to become the first quarterback selected in next month’s NFL draft is apparently down to three players: Central Florida’s Blake Bortles, Louisville’s Teddy Bridgewater and Texas A&M’s Johnny Manziel.

But according to quarterback guru George Whitfield, who recently visited LSU to speak at a coaches clinic, there easily could have been another contender had Tigers quarterback Zach Mettenberger avoided the late-season injury that prevented him from showing off in postseason all-star games and at the pre-draft combine.

“If he was healthy, I think he’s right in this,” said Whitfield, who tutored Manziel and Virginia Tech’s Logan Thomas this year, after working with such prospects as Cam Newton and Andrew Luck in previous draft cycles. “I don’t think it’s a conversation of three, it could be a conversation of four if Zach was healthy coming down the back stretch. But I don’t think it’s going to be a shock at all if you see him go in the top couple rounds. Not at all. I think somebody’s going to get a great return on investment.”

At LSU’s pro day on Wednesday, Mettenberger gets his first major opportunity to prove that the knee he injured in the regular-season finale against Arkansas is stable. He already has proven that his arm is NFL caliber, which is why some draft projections have Mettenberger going as high as the second round after a standout senior season.

Mettenberger (3,082 passing yards, 22 touchdowns, eight interceptions) was sixth among FBS quarterbacks with an 85.1 Total Quarterback Rating last season. According to ESPN Stats and Information, he made the biggest jump of any qualified FBS quarterback after ranking 80th out of 122 qualified quarterbacks with a 47.1 Total QBR in 2012.

“I think he’s one of the best quarterbacks in this draft,” Whitfield said. “I thought the year he had and the growth he had this year, especially with [LSU offensive coordinator] Cam Cameron, just getting a chance to get out there and operate in that system -- [and to] have more responsibility. He was better in the pocket. It was just a shame he did take that injury toward the end of the season, but he just looked more confident, and he wasn’t just a big guy [who] was pitching anymore.”

Mettenberger is just one member of a large group of LSU prospects who will work out in front of NFL scouts, coaches and player personnel executives on Wednesday. Among those expected to participate are running backs Jeremy Hill, J.C. Copeland and Alfred Blue, receivers Odell Beckham, Jarvis Landry and Kadron Boone, defensive linemen Anthony Johnson and Ego Ferguson, linebacker Lamin Barrow, safety Craig Loston and offensive lineman Trai Turner.

ESPN Scouts Inc. rates seven of them among the draft’s top 150 prospects: Beckham (No. 21), Landry (47), Hill (69), Turner (109), Loston (110), Ferguson (120) and Johnson (139).

Let’s take a closer look at three of them -- Mettenberger, Beckham and Hill -- with a statistical assist from ESPN Stats and Info.

ZACH METTENBERGER

In his first season working with Cameron, Mettenberger greatly improved as a downfield passer. He raised his completion percentage on throws of 15 yards or longer 14 points, to 53.4 percent, in 2013. Among ESPN’s top-10 quarterback prospects in this draft, only Clemson’s Tajh Boyd (53.7 percent) completed a higher percentage of long balls. Of the 10, Mettenberger had by far the highest percentage of total completions (67.7) travel at least 10 yards. Bridgewater was next at 57.1.

He was also outstanding against the blitz and on third down -- assets that should help convince a team looking for a pro-style pocket passer to keep him in mind. Mettenberger (57-for-85, 883 yards, eight touchdowns, two interceptions against blitzing defenses) had the second-highest completion percentage (67.1) against the blitz of any of the top-10 quarterbacks. And on third down, his 53.7 conversion percentage was the best of the bunch. Mettenberger went 58-for-89 with nine touchdowns and one interception on third down, and his 65.2 completion percentage in those situations was third among the top-10 quarterbacks.

JEREMY HILL

Because of the declining value attached to running backs in the NFL, it seems entirely likely that no running backs will go in the first round of this draft. Last year, the first running back went at No. 37 -- the latest the first running back was picked in the common draft era.

Ohio State’s Carlos Hyde is generally considered the top running back prospect in this draft, although Hill’s physical ability makes him an enticing target.

Hill faced eight or more defenders in a stacked box on nearly half of his carries last season (96 of 203), and yet, he still averaged an AQ-best 8 yards per rush in those situations and scored 15 touchdowns.

He was also a phenomenal between-the-tackles runner, picking up 7.9 yards per carry on runs up the middle, with about one in every five (24 of 118) going for at least 10 yards. On runs outside the tackles, Hill had 16 of 85 attempts go for at least 10 yards.

ODELL BECKHAM

Beckham is one of the draft’s most explosive playmakers, which is why ESPN’s Mel Kiper Jr. had him going 18th overall to the New York Jets in his most recent mock draft. He and Landry are both among the 15 wideouts who rank among Scouts Inc.’s Top 100 players -- the most receivers in the top 100 since 2005.

Beckham (59 catches, 1,152 yards, eight touchdowns, 178.1 all-purpose ypg last season) had an AQ-high 26 receptions on passes thrown at least 15 yards last season. He had at least two catches that covered such a distance in seven of 13 games in 2013, which certainly speaks to the big-play ability that has him so high on Kiper’s mock draft board.