FOXBORO -- Of all the numbers, statistics that get volleyed in the Tom Brady-Peyton Manning rivalry, there's one in particular that's quietly working to dominate the discussion.
Age.
So it's two numbers, really. Brady turned 35 to raucous training camp cheers this August. Manning is 36.
The Patriots quarterback has said several times that he wants to play until he's 40 at least. And why not? Warren Moon was 44 years and 27 days old when he made his last start.
Wednesday, four days before Manning's Broncos charge into town, Brady was asked why in the world he'd want to do such a thing. Why would he want to play such a physically punishing game for what would be 18 seasons?
"Play football?" he asked, with a barely mocking lilt to his tone.
The crowd of reporters laughed knowingly with the three-time Super Bowl champion.
New England Patriots
"It's a great sport," he relented. "I love coming to work every day. I love the challenge that the weeks bring -- the mental challenge, the physical challenge. I love the training. I love being around my teammates.
"There's just not much else out there, other than my family. It's like the abyss, you know? There's nothing else."
That phrase -- "The Abyss" -- was a bit jarring. It made you hope for hyperbole from the quarterback, or maybe some unintentional melodrama.
But it's probably impossible to imagine the depth of an abyss, the swallowing darkness of it, unless you're forced to look down inside.
Maybe that's what happened to Manning when he was injured. Maybe the broken down nerves in his neck and multiple surgeries forced Manning's toes over the edge and he didn't like what he saw.
Nobody outside of his circle knows. Brady could barely hazard a guess himself.
"I know, just speaking to him a few times, his love for the game and his love for the competition obviously exceeds whatever he may feel, or whatever he may not feel. I don't even know what he feels; I haven't talked to him about that other than, I'm sure he's healthy enough to play or else they wouldn't clear him to play.
"I have a lot of respect for him."
Opponents in battle, but perhaps on the same side in a larger war.