The age thing.
You see, Weeden is 28 - same as NFL MVP Aaron Rodgers. At an age when many NFL quarterbacks are peaking, Weeden will just be starting his professional football career.
Still, the early consensus on Weeden among the so-called experts is he could go as soon as the second round or as late as the fourth in April's draft.
At 6-foot-4 and 222 pounds, he's got ideal NFL size and a strong, accurate arm. The knocks on him: he doesn't have much mobility and - like many college quaterbacks - his mechanics need work.
And he's 28 years old.
Weeden is working on his speed and agility. He's working on his arm strength and foot work.
His age? Nothing he can do about that.
"I used to think it was more of an issue than it really is," Weeden said Tuesday, the day before he was to fly to Indianapolis for the NFL combine, which starts Thursday.
Weeden was a second-round draft pick by the New York Yankees out of high school in Oklahoma City in 2002 and pitched for five years in the minors before going back to school.
He's got six years minimum on most of the other players at the combine and, as far as he's concerned, that's not a negative.
"I think my age is an advantage. Being older, being more mature. I've already been a pro. I've had to deal with the failures and success of playing baseball. I've overcome those failures and dealt with the success," he said. "I think I'll be able to take on more early on."
Weeden decided after playing Class-A ball in the Royals system in 2006 that it was time to try something else. He didn't want to be a career minor leaguer and still had the itch to play football.
Oklahoma State quickly scooped him up. He redshirted in 2007, was a backup in
08 and09, before taking over as the starter in 2010.
In two years directing the Cowboys' spread offense, he passed for 9,004 yards and 71 touchdowns with 26 interceptions.
He also got married in 2009 to Melanie Meuser. They don't have kids, yet. He figures after he gets a job in the NFL and finds out where he and Melanie will be living, they'll start a family.
Right now his job is trying to get a job and that's how he is approaching the combine.
"There are 32 corporations there I have to try to impress. I won't let the process overwhelm me. I understand it's a business. It's my job," he said.
The quarterbacks go on display at the combine on Sunday.
Weeden said he was "leaning toward" going through the throwing drills. Many top prospects skip the passing tests at the combine, choosing instead to throw under conditions they can control at private workouts.
Weeden said he has no reason to worry.
"That's my strength," he said. "That's what I do best."
He also plans to participate in pro day in back in Stillwater on March 9. After that, he likely will have private workouts for and visits to teams that are considering drafting him.
There will no doubt be teams interested, but how many could very well be limited by his age.
Weeden inevitably gets compared to Chris Weinke, who took a similar path to college football. Weinke won the Heisman Trophy at Florida State in 2000 at the age of 28, then was drafted in the fourth round by the Carolina Panthers.
Weeden said plenty of quarterbacks play well into their mid-30s, so there's no reason he can't have a good 10-year career in the NFL.
"I don't have much to harp on or any other red flags other than my age," Weeden said. "I have a lot of football left in my tank."
Follow Ralph D. Russo at www.Twitter.com/ralphDrussoAP