The safety has already practised with his new teammates, with Ryan expressing his delight at signing a man he coached while defensive co-ordinator of the Baltimore Ravens.
Ryan told NFL.com: "He'll be a great signing for us. He's gonna help this football team, without question. He's in outstanding shape and it's clear he still moves well.
"Obviously he's not going to play every snap. He's not going to start. But I was encouraged by what I remembered and everything else. But in a way, it's not surprising [that he's still capable]."
Ryan also hinted that Reed could see action as early as Sunday, when the Jets meet divisional rivals the Buffalo Bills.