Since Tyron Smith was the Cowboys' first-round draft pick, he's established himself as a beast at left tackle and as one of the best offensive linemen in football.
In Pro Football Focus' postseason ratings for the 2015 season, they named Smith as the league's second-best offensive lineman and the second best run-blocking lineman in all of football. The only player in front of Smith? Perennial All-Pro Joe Thomas of the Cleveland Browns, who was recognized as the best pass protector in the league. Ultimately, Thomas' pass-blocking proficiency outweighed Smith's run-blocking ability.
Here's what the highly respected folks at PFF said about Smith:
As he did for our All-Pro team, Tyron Smith comes in right behind Thomas when it comes time to hand out another honor. Evaluating the two beasts was closer than you'd imagine, with Smith's exceptional run blocking (96.8, best among offensive tackles) hard to overlook, but it was Thomas' superior pass protection that gave the veteran the upper hand. Smith didn't have a single game graded below -1.0 (0.0 is average) as a run blocker all season, and while he allowed two fewer pressures than Thomas, he also pass-protected for 124 fewer snaps. On a per snap basis, Thomas' edge as a pass protector is as comfortable as Smith's is as a run blocker. After a tough first year at left tackle in 2012, Smith has now established himself as one of the league's elite blockers.
It's now a well-known fact the Cowboys have one of the best offensive lines in football, and obviously Smith is a huge anchor of that.