After a couple of relatively down seasons, Nick Mangold reverted to top form in 2014 and was one of the best centers in the league in the fifteen games he suited up.
I'm not sure how much detail I will go into here because I'm not sure much detail is really necessary. He did excellent work as a run blocker. As a pass blocker, he was responsible for only 8 total pressures, second least in the league behind Max Unger. These individual things don't tell the story of Mangold's value to the line. He was between unsteady guards for the entire season. I'm not sure I would say the offensive line was a strength for the Jets, but Mangold might have been the biggest reason it was not a catastrophe. He held the middle while the guards struggled. He consistently helped Oday Aboushi and kept Aboushi afloat. He knew when to pass his man off and offer assistance when Aboushi was in trouble. Aboushi knew he could count on help from the inside.
Mangold is one of the priciest centers in the league. His 2015 cap hit is second to only Ryan Kalil. I think this is a definite case of paying for quality, though. And while I hesitate to talk about leadership without being in the locker room, Mangold by most accounts has become a very respected veteran voice. Hopefully his play continues to be high level for a long time to come, and Mangold can spend his entire career in green and white.