According to the grading system of Pro Football Focus, the Cleveland Browns offensive line has played the 3rd best in the NFL so far this season, just behind the much-improved lines of the Carolina Panthers and Atlanta Falcons. Here's what they had to say about the Browns' line play:
Pass blocking rank: 3rd
Run blocking rank: T-4th
Penalties rank: 25th
Stud: There will come a time when Joe Thomas (+13.0) doesn’t play well. That time is not yet here.
Dud: Coming back from injury, Alex Mack (-3.1) is the only Browns’ lineman with a negative grade.
Summary: The O-line remains the strength of Cleveland’s offense, although it’s somewhat disappointing that Joel Bitonio hasn’t followed up his amazing rookie year with a strong start to his sophomore campaign.
Joe Thomas was also selected as the top left tackle on PFF's All-Pro Team Through Week 4:
This isn’t the year Joe Thomas takes a step backwards, and if any one player in the NFL can be described as a constant, it’s the immovable Thomas.
Joe Thomas is playing up to his usual standard of excellence. Joel Bitonio has taken a step back but is still putting together above-average play, as are John Greco and Mitchell Schwartz. Alex Mack is the weak link at center, having taken a gigantic step back since suffering a broken fibula and ankle last season. Rookie first-round guard and center Cam Erving is waiting in the wings. I expect the Browns to keep him waiting and to give Alex Mack ample opportunity to turn things around and re-gain his pre-injury form.