2018 NFL combine primer: Kiper, McShay answer biggest questions

Will Darnold's evaluations change for not throwing at combine? (1:31)

Field Yates explains why former USC QB Sam Darnold has chosen not to throw at this week's combine. (1:31)

The NFL combine -- the most important evaluation event on the road to the 2018 NFL draft -- is here, and all the best prospects are in Indianapolis to show their stuff in front of NFL front-office personnel.

With workouts starting Friday -- here's the full schedule -- we asked ESPN NFL draft experts Mel Kiper Jr. and Todd McShay to break down what they'll have their eyes on in Indy, from the top quarterback prospects to potential fallers and risers, and more.

Click the links below to go to each section:

Top QB watch | Biggest questions | Filling in the blanks

McShay: What I'm looking for from the top six QBs

Sam Darnold, USC

Scouts Inc. position rank: No. 1

For Darnold, I'll be monitoring the little things in Indianapolis. His hand size, for one. Ball security has been an issue (14 lost fumbles in 24 starts), but that could be partly due to his mechanics as well. He's not throwing in Indianapolis, but we'll be able to see him go through athletic testing. And no, I'm not overly concerned by him not throwing. Darnold was a three-sport athlete in high school and went 20-4 at USC with a supporting cast that wasn't as amazing as some people think. His decision to not throw at the combine will have no impact on whether a team decides to draft him (or any QB).

Josh Rosen, UCLA

Scouts Inc. position rank: No. 2