"J.R. played so well last year," Cable said Tuesday on 710 ESPN Radio Seattle. "People question that, and that's foolish if you know football. He may be one of the best young guards in the game. He'll probably prove that this year."
Cable also said the team doesn't have a battle to decide either of the starting guard spots. Barring injury, Sweezy will start and right guard and James Carpenter will start at left guard.
"Carp is healthy now," Cable said. "He's really playing at a much different level and pace."
But the team does have a battle for the starting spot at right tackle between second-year player Michael Bowie and Missouri rookie Justin Britt.
It's going to be maybe the best battle I've had since I've been in Seattle," Cable said. "Justin is making improvement leaps bounds every day. He's really bright and never makes the same mistake twice. He likes to grind.
"Mike needs to take care of his conditioning and weight. Justin won't give him and inch and it's on. It will be settled in the preseason."