SB Nation's Gang Green Nation says losing Revis is "losing the ability to lock down half the field."
There is no substitute for what he brings to the Jets. The Jets have one of the best cornerback tandems in the NFL but the drop from Revis/Cromartie to Cromartie/Wilson is very significant. It also means that players like Trufant and Lankster will have to step up. The blue side of New York may be experts at 'next guy up' but I haven't seen that from the Jets.
I can't explain how important Revis is. He allows the defense to blitz more and he allows us to roll coverage to the other side. Without him, the pass defense will take a big hit and I hate putting too much emphasis on one player but losing Revis is like having your right leg cut off. I can't think of a more valuable player to lose or a harder player to replace.
Gang Green Nation is right. This is perhaps the most devastating non-quarterback injury in the league so far this year, and likely the rest of the year.