"We have a very young team," Johnson told the New York Daily News. "I think it's the third-youngest team in the NFL and it's not an excuse.
"You're going to have games like that with a young quarterback and young team — seven new players on defense — so it's going to take them a while to coalesce.
"But they're improving rapidly, and I think the coaches are very happy with the progress."
Rex Ryan's side face the New Orleans Saints on Sunday.