For the second time in three days and the third time in less than a week, the Vikings have sent, among others, coach Mike Zimmer, offensive coordinator Norv Turner and General Manager Rick Spielman on the road to watch a quarterback during his college pro day.

After watching Alabama's A.J. McCarron last week and Louisville's Teddy Bridgewater on Monday, the Vikings were among the masses that went to Central Florida today for Blake Bortles' workout. They'll also be at Johnny Manziel's pro day on March 27.

According to NFL Network analyst Mike Mayock, who covered today's workout, Bortles was satisfactory. And that's a step up from Mayock's level of disappointment with Bridgewater's shaky and inaccurate effort on Monday.

"I thought [the workout] looked like it was supposed to look like," Mayock said of Bortles' pro day. "When you're talking about a 6-foot-5, 229-pound quarterback, he's athletic, and that's obvious. … I thought it was really solid from every perspective. … Really good arm strength. I wouldn't say elite, but I'd say really good. I think the word for this kid is `potential.' Young, he's got a lot of work to do and I can see that on tape. But what I saw out there is he's potentially a franchise quarterback."

The word "potentially" must feel frightening to the men who must make the call on whether to take this guy or any of the other top quarterbacks near or at the top of the draft on May 8. Make the right call and you turn around your franchise, save your job and raise your guru status. Blow the pick and you're right back in this spot three years later, assuming you don't get fired.

Making that pick can be the toughest decision that an NFL executive has to make. ESPN's Ben Goessling did a strong piece on why quarterbacks are so difficult to assess. It made me think of answers that Tony Romo gave to a couple of questions I posed to him during a conference call prior to last year's Vikings-Cowboys game.

Romo isn't the greatest quarterback in the game today, but you have to admit he's become a ton or two better than anyone would ever expect from an undrafted free agent.

I asked Romo what it is about quarterbacks and the draft selection process that can lead to No. 1 overall picks flopping and undrafted free-agents flourishing.

"I think sometimes only certain people can evaluate the quarterback position at a high level," Romo said. "I think it's a very tough thing to do because there are so many things that go into it. And I think it's a difficult position to gauge. Just [the offensive] system alone dictates differing decision-making processes and I think that unless you're really the guy coaching him and teaching him, you don't necessarily know his strengths and negatives."

I then asked Romo for the one trait he would look for if he were in charge of drafting a quarterback coming out of college?

"Instincts," he said. "Just their ability to get through progressions at a fast rate. You can always work on accuracy, you can always work on footwork. You can get guys to do the right things and be leaders and all that stuff. But inherently what you can't teach him is to see the field quickly, react quickly and get through stuff fast. That's where I find that [teams] just miss the mark the most times with young guys."

Poise and a quick thought process when all heck is breaking loose. Find that and you find the key ingredient for greatness at quarterback. And, no, there isn't a combine drill that measures this trait.