He certainly won't make it worse.
He's a very good veteran corner who's going to play mostly in the nickle/dime against the slot. While we've had some admirable play from others in his absence, he's only going to make the defense better imo.
If we can't get one yard in the running game when we need it, it could cost us a game or two this season. Our OL lacks nastiness, period. I remember when our run blocking was superb back in the day. The big nasties would eat glass and crap barbed wire. Now they apparently eat marshmallows wear roller skates that only work in one direction...backwards.