GREEN BAY -- There may not be a position in the NFL draft that causes more general managers and personnel gurus to reach for the antacid more than wide receiver.

"It has the biggest mortality rate of any position percentage-wise," former Dallas Cowboys personnel director Gil Brandt, now a draft analyst for NFL.com, said at the league's annual scouting combine. "So buyer beware."

Invariably, there are great ones waiting to be had. But there are also more first-round mistakes made on the position than any other. And rookies at the position often struggle to make an impact.

"There's some teams that just are dead set against taking a receiver in the first round because history shows how many great ones are around in the second and third," St. Louis Rams vice president of player personnel Billy Devaney said. "The difference-maker? Those guys are hard to find, the guy who can score touchdowns, if you really think you have the guy, you have to go ahead and take him."

But who is that guy? And who's the bust-in-waiting?

Take this year, for example. Five receivers -- Michigan State's Devin Thomas, Texas' Limas Sweed, Oklahoma's Malcolm Kelly, Indiana's James Hardy and California's DeSean Jackson -- have a chance of being drafted in the first round, although none is expected to be taken in the top 10.

They all come with serious questions: Thomas started only one year for the Spartans; Sweed missed the Longhorns' last seven games with a wrist injury; Kelly suffered a torn quadriceps and was limited in his predraft workouts; Jackson is super-fast but lack of size is a big issue; and Hardy has great size but lacks speed.

"Which one do you like?" Tampa Bay Buccaneers coach Jon Gruden said. "I mean, the guy at Cal (Jackson) is 169 pounds. Is he going to be big enough? He's certainly fast as hell. He'd be a hell of a returner. The guy at Indiana (James Hardy) is big. Every film you pick up there's another touchdown. Is he fast enough? So that's a tough call. It always is, though."

Indeed, six wide receivers went in the first round last year, but none made an overwhelming impact. The most productive of the bunch was the Kansas City Chiefs' Dwayne Bowe, the 23rd overall pick and the third receiver taken, who led all rookies with 70 receptions for 995 yards and five touchdowns. Calvin Johnson, the No. 2 overall pick, had only 48 receptions for 765 yards and four touchdowns for the Detroit Lions.

"I have mixed emotions," NFL Network draft analyst Mike Mayock said of this year's receiver crop. "There might be three or four first-rounders (taken in) this draft, but I'm not convinced there is a true first-round wide receiver. Philosophically, I'm getting to the point where I think you can drop down into the third or fourth round and get a James Jones (the Green Bay Packers' third-round pick last year) who can contribute."

While Buffalo Bills coach Dick Jauron called this year's class "pretty deep," he also acknowledged, "I don't know how many great players there are -- you never know that. (But) I think you 're going to get a good receiver down the line, a little deeper than what I would consider normal."

Jackson, despite being listed at just 5-foot-9 and 169 pounds, might be the most intriguing prospect of the bunch. Despite the trend toward bigger receivers, he is convinced he will succeed at the next level.

"It's not going to hurt me. You can put on my film and actually see I play bigger than what I really am," said Jackson, who spent time working with legendary receiver Jerry Rice earlier this spring. "If there's something I have to work on, something I feel I could improve on, (it's to) get stronger and put a little bulk to me. But heart, dedication and my will to be great is something I have."

Size isn't a problem at tight end, where the first one might not come off the board until late in the first round but the position is deep, with five -- Purdue's Dustin Keller, USC's Fred Davis, Texas A&M's Martellus Bennett, Notre Dame's John Carlson, and Texas' Jermichael Finley possibly going on the first day.

"It's a good group. But the one thing that's unique this year -- and I think you'll see it for the future -- is that with a lot of these college offenses going to three- and four-receiver sets, (so) you're going to see more tight ends flexed out or detached from the line of scrimmage. They're used more as receivers rather than really blocking tight ends," San Francisco 49ers GM Scot McCloughan said.

"When you get (end of) the season and want to make a playoff run, you have to be able to run the football. And the way we approach it with (tight end) Vernon Davis, he's an offensive linemen on third-and short. I think in college you don't see it as much. But in the pros you can't lose sight of that aspect."

Nor can you lose sight of how a good tight end can be a security blanket for his quarterback.

"I feel like every quarterback definitely needs a tight end he can rely on," Davis said. "A receiver can be double-teamed and you 've got other positions (available). If you've got a (good) tight end, you can rely on him to make a big catch or make a big play. There's a lot of athletic tight ends now and it helps a lot to have that kind of guy to make those kinds of plays."

QUICK READ: WRS/TES
THE TOP FIVE WRS
Devin Thomas, left, Michigan State (6-foot-1 7⁄8, 216 pounds, 4.42 seconds in the 40-yard dash): Has terrific size and showed big-play ability in catching 79 passes for 1,260 yards and eight TDs last year, but there's some concern he's a one-year wonder after transferring from a junior college.

Limas Sweed, Texas (6-3 7⁄8, 215, 4.54): Big, gifted receiver who was limited by a wrist injury all season last year and finished with just 19 receptions for 306 yards.

Malcolm Kelly, Oklahoma (6-3 3⁄4, 228, 4.55): Inconsistent, high-risk player who caught 49 passes for 821 yards and nine TDs last year as a junior.

James Hardy, Indiana (6-5 3⁄8, 217, 4.54): Set Indiana school record with 36 career TD receptions; despite incredible size, lacks focus and maturity.

DeSean Jackson, California (5-93⁄4, 169, 4.39): Electrifying player whose lack of size makes durability a huge question. Could have immediate impact as punt returner.

THE TOP FIVE TES
Dustin Keller, Purdue (6-2, 242, 4.57): Athletic, competitive player who caught 68 passes for 881 yards and seven TDs last season and whose strong scouting combine performance may force teams to overlook lack of ideal size.

Fred Davis, left, USC (6-3, 255, 4.65): Had almost identical numbers to Keller (62-881-8) and won the Mackey Award for top TE in the nation.

Martellus Bennett, Texas A&M (6-61⁄8, 259, 4.72): Former basketball player who has terrific size and athleticism but lacks top-end speed.

John Carlson, Notre Dame (6-51⁄8, 251, 4.88): More productive as a junior on a better Irish team but pass-catching ability and football IQ remain impressive.

Jermichael Finley, Texas (6-41/2, 243, 4.85): Redshirt sophomore who might've benefited from another year of college but big game against Oklahoma (four catches, 149 yards, TD) was a glimpse into how good he can be.

THE PACKERS' PERSPECTIVE
The Packers' ''Big Five'' at receiver — Donald Driver, Greg Jennings, James Jones, Ruvell Martin and Koren Robinson — is the best quintet in the league. That said, GM Ted Thompson isn't afraid to create more competition, so there's no ruling out a wideout in the draft, especially given how many good ones are available.

The clear need is at tight end, where 2000 first-round pick Bubba Franks was released after yet another unproductive season, leaving starter Donald Lee and Tory Humphrey, who missed all of last season with a broken ankle, as the only two tight ends on the roster. In a draft with plenty of appealing options at the position, don't be surprised if the Packers take at least one, maybe even on Day 1.