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For at least a couple of generations of SportsNation, Billy Sims is that loud guy (Boomer!) who stood behind Sam Bradford at the Heisman ceremony two years ago. But for some, he's still the guy who starred at Oklahoma and then made the Pro Bowl after rushing for 1,303 yards and 13 touchdowns after the Lions made him the No. 1 overall pick in the 1980 draft. If you don't remember that part, it's because he was out of the league by 1985.

Needless to say, Clippers fans hope their former Oklahoma star follows a different path.

Sims is part of an exclusive club, even if it's one nobody wants a part of. Some No. 1 overall picks just can't cut it in the pros (we're looking at you, JaMarcus). But others fail to live up to their potential for reasons beyond their control. So scanning the last 30 years, which No. 1 picks would have ranked highest in the pantheon of all-time greats if not for injuries?

• Steve Emtman: No. 1 pick in 1992 by Colts
• Bo Jackson: No. 1 pick in 1986 by Buccaneers
• Larry Johnson: No. 1 pick in 1991 by Hornets
• Eric Lindros: No. 1 pick in 1991 by Nordiques
• Danny Manning: No. 1 pick in 1988 by Clippers
• Ben McDonald: No. 1 pick in 1989 by Orioles
• Yao Ming: No. 1 pick in 2002 by Rockets
• Greg Oden: No. 1 pick in 2007 by Trail Blazers
• Ralph Sampson: No. 1 pick in 1983 by Rockets
• Billy Sims: No. 1 pick in 1980 NFL draft by Lions

We've already noted that SportsNation is optimistic it hasn't seen the last of Yao Ming in the NBA (although that begs the question whether Nets fans would like to be optimistic they have seen the last of Yi Jianlian). But even if Yao makes it back, he could be one of the great what-if players of all time. Our five candidates for the top spot.

Sam Bowie: Essentially a seven-foot punchline at this point, Bowie was doomed the minute he was picked ahead of Michael Jordan. But as Marc Stein recounted, leg injuries -- not Jordan -- were what cost him a chance to make a name for himself.

Bo Jackson: What highlights are more iconic than Jackson running up a wall on the baseball diamond or over Brian Bosworth on the football field? He was 28 when he suffered his hip injury, which isn't young for a running back, but he didn't have a lot of NFL miles on his legs.

Mark Prior: He may not be technically done, but Prior's days as a Cooperstown lock are long gone. At 22, he went 18-6 with a 2.43 ERA and 245 strikeouts in 211 innings. Slowed by countless injuries, he's won just 18 games since that season.

Sterling Sharpe: He still ranks in the top 50 all time in NFL receptions and never played a game after the age of 29 because of a neck injury. Imagine his numbers with six or seven more seasons with Brett Favre in the quarterback's prime.

Bill Walton: One of the greatest college players of all time, Walton wasn't exactly Bowie in the pros, leading the Trail Blazers to a title in 1977 and winning MVP in 1978, but chronic injuries robbed him of most of his prime years.

• Yao is just one more name in a long list of really tall guys whose bodies seemed to break down under the grind of professional basketball. Other than Kareem Abdul-Jabbar and maybe Mark Eaton, the list is short when you get above 7-foot-2 or 7-foot-3. But when it comes to height, SportsNation says teams will always gamble.

“

Take another lesson from Bill Walton, Yao. Don't try to come back just because you feel guilty or responsible. Let that thing heal. And come off the bench like Walton or take every other game off like Shaq if you need to. Everybody criticized Kareem for taking it easy, jogging up and down the floor. Well the guy was 7'3" and his body lasted 20 years in the league.

” -- thechendaddy

“

The NBA with its hardwood floors and 82 game seasons are just not meant for 7 and a half footers. Shaq is probably the best example in this era of longevity for people 7 feet and beyond, and he is 7'1. On top of that Yao also has Olympic priorities with China!!!

” -- trunkmonkey1980