Jets Vs. 49ers, key matchups: Darrelle Revis' Injury leaves Jets secondary vulnerable

So this is life without Darrelle Revis for the New York Jets. Gang Green's defense must change; they can no longer ignore an entire side of the field and leave it to Revis. The Island is closed for the remainder of the year.

This makes the Jets a much more ordinary defense. Corners Antonio Cromartie and Kyle Wilson are talented players, but they'll have less help than they used to in their previously scaled-back roles. The offseason additions of LaRon Landry and Yeremiah Bell now seem even more crucial. And oh yeah, running back Joe McKnight is now playing cornerback.

On Sunday against the San Francisco 49ers, there's a good chance this Jets secondary will get tested early and often. The 49ers are a bruising running team, but they do have talent in the receiving corps and have one of the best tight ends in football in Vernon Davis. How the Jets contain the 49ers' passing attack leads our look at the key matchups to Sunday's game.

Jets' Secondary vs. 49ers' WRs/Alex Smith

The Jets' rushing defense has not been great so far this season, but I don't think they're going to have as much trouble with the Niners' running attack as some others. I think the Jets match up well up front with a north-south running attack. To me, the Niners will take shots at the Jets' secondary early and often. They'll look to pick on Kyle Wilson, who has yet to prove he's worthy of the first round pick the Jets used on him in 2010. Michael Crabtree and Mario Manningham are guys who can get open and Alex Smith, while not spectacular, has become incredibly efficient under Jim Harbaugh. If you give Smith time and he has open receivers to throw to, he'll hit them. Can the Jets' makeshift secondary cover well enough to make up for the lack of pass rush that's sure to plague them once again this week? Without Revis, the Jets won't be able to blitz as often (which might be a good thing, because by my calculations it's been about 610 defensive snaps since Rex Ryan dialed up a blitz that actually did something), so they'll need to cover. And then there's Davis, who has a chance for a big day given the Jets' struggles at stopping tight ends. If the Niners can move the ball downfield in chunks on the Jets' defense, it will probably be a long day for Gang Green.

Shonn Greene vs. Bilal Powell vs. Tim Tebow

Yes, these guys play for the same team, but I'm anxious to see how the Jets deploy their backfield. I have to think that the Jets' coaches are frightened of Mark Sanchez bumbling this game away. They shouldn't be, because he's their quarterback and that's no way to play football in 2012, but you know Rex and Co. are hammering home the "We cannot turn the ball over at all, a punt is a good play" mantra this week. That means a heavy dose of the running game, which has been pretty putrid all season and is going up against one of the league's toughest and best defenses. The Jets would be best served using Powell, who I outlined yesterday is just a better and more efficient back than Greene at this point, who is not worthy of the carries he receives. And then there's Tebow. I think this is the game he features the most in. I'm not sure it's a great matchup for him at all. But I have a feeling the Jets' coaches will force-feed the Wildcat on Sunday. Although, it would be a perfect scenario for the supposed "quarterback" to actually throw the ball.

Mark Sanchez vs. MetLife Stadium

Sanchez will probably struggle in this one. That's nothing to be ashamed of - Aaron Rodgers was shut down, at home, by this same defense in Week 1. But the MetLife Stadium won't care. If the Jets have six points at halftime, it's probably going to get a little ugly in there. Sanchez has to stand tall, stay confident and shake off any distractions the crowd may present. Of course he could have the Jets faithful bowing down at him if he goes out and kills it, but I just don't expect that to happen. If Sanchez has a rough day, he can't let it snowball and wreck his season, which is what likely happened last year in Week 4 at Baltimore.