Just like with the Colts' first pick of the 2013 draft, Ryan Grigson didn't go with what looked like the best value at 86 overall. But just like in the first day of the draft, he knew who he wanted and wasted no time in snatching him up once the Colts were on the clock.
Thornton is one of the bigger guards available in this year's draft at 6'3", 320 pounds. Thornton used that size all across the line at the University of Illinois, where he played guard for three years before sliding outside to tackle during his senior year. But despite his size, he doesn't have quite the length necessary to play tackle in the NFL, which likely slots him at guard in Indianapolis.
Where in Indy?
With the signing of Donald Thomas in free agency to play left guard, the Colts now look to right guard, where Mike McGlynn started in 2012. McGlynn was Pro Football Focus' worst guard (subscription required) in the league last season, and the Colts desperately need to improve there with players like J.J. Watt in the division.
With Thornton, the Colts now look to have a "great competition" at the position in training camp with McGlynn, Thornton, Joe Reitz, and Ben Ijalana all competing.
If the Colts truly are going to become more of a power-running team under Pep Hamilton, Thornton is a very good fit. Not only does Thornton have the size, as mentioned above, but he also is very strong (27 reps in the bench press at the combine) and can be a mauler in the run game.
That upper-body strength allows Thornton to latch onto defenders once he is engaged and rarely allow them to shed the block. Thornton is tenacious and is very often seen finishing blocks to the ground, both in the run game and in pass protection.
Even more impressive for Thornton, arguably, is his foot quickness. With his height and weight, his three cone drill time at the combine of 7.45 seconds (seventh among offensive linemen) is very impressive, allowing him to move up into the second level quickly in the run game as well as handle quick rushers in the interior defensive line.
Thornton's quick feet also lead to a quick burst off the line, which, when combined with his upper-body strength, allows him to quickly get control of his man.
The biggest concern for Thornton will be his tendency to either stand straight up or bend at the waist (instead of knees), which is a common problem for taller linemen.
When in pass protection he will need to get down with his knees bent more quickly, or he will be very vulnerable to bull rushes in the NFL. In run-blocking, his bending at the waist can lead to defenders spinning out of the block quickly, instead of Thornton maintaining engagement and holding the hole open.
Overall, the Colts addressed their biggest need here with Mike McGlynn arguably being the worst projected starter at right guard. Thornton has size and athleticism that cannot be coached, and he will provide competition and depth on the interior offensive line at the very least.