Don't get it twisted: Teams care about how a quarterback looks throwing the ball during combine workouts. The evaluators might not focus on pure accuracy, as the passers have never worked with the receivers to which they are throwing. But if the ball comes out of a prospect's hand poorly in an ideal throwing environment, or if their footwork appears slow or sloppy, or they appear unable to adjust to coaching during the event, teams will make a note of it.
Then there's the interview process and medical checks that help teams understand the mental and physical attributes that each prospect possesses. While all quarterbacks are under scrutiny at the combine, these five have the most to prove to make believers out of teams in need of a leader on offense.
NOTE: Click on each player's name for a full combine scouting report.
Kizer has the potential to be one of the draft's top picks, but his inconsistent play as a redshirt sophomore will make teams uneasy about selecting him that high in the draft. Against Texas in the season opener, he looked unstoppable. Against North Carolina State and Stanford, Kizer looked lost and he barely completed 50 percent of his passes in the team's losses to USC and Virginia Tech to end the year. However, it's easy for coaches to fall in love with a smart player with prototypical size and arm strength like Kizer. In a better learning environment than he had in South Bend, coaches will believe they can mold those attributes into a very good starting quarterback. Kizer has a chance to wow everyone at the combine with his skill set and push himself to the top of quarterback boards across the NFL.
The fact that Trubisky was only a one-year starter at UNC is not his fault (Marquise Williams was a team leader and a darn good player). However, the lack of game action means every opportunity Trubisky has to throw in front of scouts becomes that much more important. It's probable that he will look athletic, and he's likely to throw a nice ball inside the dome. But his measurements will be important (teams look for the 6-foot-2, 215-pound minimum at the position) as will the football knowledge he shows during the interview process.
Despite all that Watson achieved in the past three seasons, the combine still matters for his draft stock. He's a leader with solid intangibles, but like all quarterbacks, displaying his knowledge of coverages on a white board in front of NFL teams is a crucial step in showing he can process information. Measuring at least 6-foot-2, 215 pounds would be helpful in terms of teams' belief that he can stay healthy while taking hits from NFL defenders. Having the ball come out of his hand with some pop when he throws is also a must, and looking comfortable while dropping back from under center would be a major help to his cause. Watson won't be able to quiet doubters who believe he fails when under pressure in the pocket because there'll be no pass rush coming for him at the combine. But short of that, a strong week in Indy (along with his on-field resume while at Clemson) will go a long way toward convincing teams he's worthy of a top-five selection.
As intriguing as Mahomes' skill set is, his freelancing and poor throwing mechanics will make quarterback coaches throughout the NFL queasy. Setting his feet and consistently delivering an accurate throw (again, within reason given the situation) will give coaches and scouts hope about his NFL prospects. The combine throwing session doesn't mimic live action, where he might return to his habits of throwing off his back foot, throwing sidearm and throwing into traffic, but showing out well in Indy will be a good start for him. Mahomes' interviews will be important, as well, because of teams' wariness of Air Raid-system quarterbacks, so he'll need to show a sound understanding of an NFL offense.
Another one-year starter at the FBS level, (began at Air Force until injury led him to transfer to junior college), Evans could make a lot of fans at the combine. He's a smart player who brings athleticism and a live arm to the party. If he impresses on the field, in workouts, and at team interviews, we could be looking at the player teams will point to as the next mid-round pick with starter-quality attributes -- aka the next Dak Prescott.