Best case - he's covering for someone else and risking jail and the end of his career. If so, let's hope he comes to his senses, cooperates fully, and pleads to obstructing the investigation.
Worst case - he was involved.
Either way, the truth will come out. Whoever is least culpable will talk and get a reduced sentence. The rest will spend their lives with Whitey and Dzokar.
If there's strong evidence against him, the potential defense could get interesting. PTSD? Concussions? 'Roid Rage? Painkillers? All of the above?
"The Patriots made me play hurt. I had concussions. I was taking painkillers and steroids. I'm not responsible for my actions."
I don't think those arguments would work, but it could be the first use of them that I'm aware of.