Hang on, folks. The first round of the NFL draft is about to get even more unpredictable.

"I think this is going to be one of the most intriguing drafts that I'm going to be associated with," said Vikings General Manager Rick Spielman, now in his 23rd season as an NFL executive.

Whether Thursday night's action tops the record 19 trades that marked the first round of last year's draft remains to be seen. But a deep draft lacking in superstar power does have several teams wishing to move down for more picks and better value later on.

The Vikings have the 23rd and 25th picks and don't want to trade up. But they're in prime position and more than willing to trade down with teams that will want to move back into the first round for a quarterback. Of course, that's assuming the top players in a lackluster quarterback class aren't prematurely gobbled up by desperate teams trying to generate at least some sort of hope in a quarterback-driven league.

"A lot of what happens on who comes down to us, I think, is predicated on what happens with the quarterbacks," Spielman said. "We've prepared ourselves in case there are no quarterbacks taken by the time we pick and what kind of scenario we will be facing [if there are]."

Spielman joked that there are 8,000 different scenarios that could unfold in this particular first round. Whatever the actual number is, the Vikings' scouting department and coaching staff probably have discussed them all while tucked in their Winter Park draft bunker in recent weeks.

"Just looking at their faces right now, you can tell everybody is just tired of me," Spielman said. "Tired of me asking questions, not for the first time but probably for the 500th time. 'What are we doing on this? Are we sure about this?' "

Even without all the trade possibilities, this first round seems to have an inordinate amount of variables. Such as:

• Medical concerns about several players, including Utah defensive tackle Star Lotulelei (heart condition), Georgia outside linebacker Jarvis Jones (spinal condition), Houston cornerback D.J. Hayden (near-fatal torn blood vessel in his chest), Cal receiver Keenan Allen (knee) and Alabama cornerback Dee Milliner (shoulder).

• Character concerns about Georgia middle linebacker Alec Ogletree, who was suspended twice, failed a drug test and, to top it off, was charged with drunken driving in February.

• The Bills' interest in Syracuse quarterback Ryan Nassib. Yeah, Bills coach Doug Marrone and his offensive coordinator, Nathaniel Hackett, coached Nassib at Syracuse last year. But would they really reach for the guy at No. 8?

• The level of the Jets' desire to replace Mark Sanchez. Is it enough to reach for West Virginia quarterback Geno Smith at No. 9 or No. 13?

• The on-field speed questions and off-the-field attention that comes with taking Notre Dame linebacker Manti Te'o. Some say he's not fast enough to be a three-down playmaker. And if he's not, is taking on his Internet girlfriend hoax story worth the distraction?

These are only a smattering of questions facing Spielman and the league's other 31 decisionmakers as they prepare for Round 1.

"It's kind of like putting a Rubik's Cube together," Spielman said.

Mark Craig • mcraig@startribune.com