The pickings seem to be pretty slim in the free agent market for offensive tackles. Jeff Backus might be among the best options out there. The Detroit left tackle is exceptionally durable, having started every game for his entire 11 year career. He was one of the few decent pieces during a brutal stretch in MoTown.
Backus would purely be a stopgap for the Jets, buying them some time to find or develop a long term answer at right tackle. At 34 he is near the end of his career. He is the prototypical guy who does everything well but nothing exceptionally. He is an adequate pass protector. Aroound 6.3% of his pass blocking plays resulted in a missed block that impacted the quarterback. That is neither great nor terrible. He has enough athletic ability to hold up fine but not enough to dominate. Moving to the right side where the pass rushers are usually not as dynamic and where the quarterback can see them coming would probably help improve his numbers. As a run blocker, he is technically sound, but he is not going to blow anybody away with his 6'5" 304 pound frame. The Lions averaged a solid 4.2 yard per run to the left side in 2011.
I think Backus would be a certain upgrade over Wayne Hunter and a decent stopgap. Unfortunately there are no slam dunk answers at right tackle so I think the Jets should take a look if the Lions do not lock him up before free agency begins.