There are five main offensive tackles in this year's draft: Anthony Castonzo, Gabe Carimi, Derek Sherrod, Tyron Smith, and Nate Solder. My personal favorite is Anthony Castonzo because he goes to the best university that's not in Boston and not actually a College. Also, he has a great blend of immediate translatable performance and upside. Another guy, however, just flew up my list.
Tyron Smith has never played left tackle. He was a right tackle at USC and he played at 290 lbs. That's extremely light for any lineman, never mind a guy who is supposed to improve and protect the quarterback's back/blindside. Well, he measured in at the combine at an impressive 307 lbs and with an arm span of 36 3/8". For the record, an arm span of 34+ is good. 36+ is just incredible. If Smith can show that he can maintain his agility with the added weight, he definitely deserves a first round look.
Smith would be able to play right tackle as Sebastian Vollmer would flip to left tackle and, if Smith improves enough, they could eventually switch back. Either way, the Patriots would have two extremely solid bookends on the offensive line. Smith was able to fully negate Cameron Jordan (the guy who's been impressing everyone at 3-4 DE) during the regular college season, which means that he's fully capable of handling NFL level defensive ends. You can watch his tape of the game here. Keep in mind that he's playing RIGHT tackle (#70).
Smith has shown a lot by arriving with gained weight, but also healthy weight. If he continues to impress at the combine, the Patriots should start moving him up their draft board.