Mel Kiper and Todd McShay preview what they're looking forward to the most at the NFL combine. (2:01)

There's no question Oklahoma Sooners quarterback Kyler Murray is the most intriguing prospect at the 2019 NFL combine. Is he shorter or lighter than the 5-foot-10, 195 pounds he's listed at by Oklahoma? Can he convince NFL decision-makers that he's focused on football and won't give it up to go back to baseball? Will he show off his arm in workouts? Will he run a 40-yard dash or compete in other athletic testing drills?

He's far from the only prospect teams will be closely watching, however, as testing gets underway Thursday. Here are five others to keep an eye on in Indianapolis:

Scouts Inc. ranking: No. 1 DS, No. 35 overall

Rapp reportedly ran a 6.57-second three-cone and a 3.88 short shuttle time last March. That would have been the third-fastest three-cone time among safeties last year, and the fastest short shuttle run by any defensive back since 2016. If he's 200 pounds, runs in the low 4.5s in the 40-yard dash and his arm length checks out, along with those kinds of times in the agility drills, he'll have the testing and tape to push for the top safety spot and the first round.

Scouts Inc. ranking: No. 6 WR, No. 49 overall