The plush, indoor field at Florham Park sat yards away, with its warmth beckoning to Denver Broncos players.
Fox opted for the outdoor field and the type of natural elements the Broncos will encounter at MetLife Stadium on Sunday.
"It was great," Fox told pool reporter Jarrett Bell after practice. "We're pretty much weather-proof. We practice in this stuff all the time. Being in Denver, we've played in a few different elements. We practiced numerous times in single digit, played in single digit, played in wind. We've practiced in snow many times. We're pretty much ready for anything."
Bell described Manning as "in command" and "precise" on his throws, unaffected by the cold.
"Very sharp," Fox said of Manning. "What I've noticed, he had to get used to weather over the past two years. I think he's done an unbelievable job, which I think people forget."