James Cook is open about being closed.

“Much won’t be said,” Cook explained. “Just let my game play.”

The Bills running back is doing just that through the first two games of his second season, entering week three 5^th in the NFL in rushing with 169 yards, including a career-high 123 in Sunday’s win against the Raiders.

“Now what we’re seeing on the field is when he puts his mind to it, he can really run the ball,” Bills head coach Sean McDermott said.

As Cook continues to develop on the field, he is slowly showing signs of opening up to those around him off of it.

“To the people I’m comfortable around, I’ll talk a lot more, but that’s just me,” Cook said. “I just stay to myself and play football.”

“He’s more like an introvert,” Bills wide receiver Stefon Diggs said. “But football-wise, he’s a baller. He has some personality, he just won’t show it to everybody.

Diggs is one of the few Cook mentioned as those he does feel comfortable enough around to open up more.

Yet there’s even less who can get him to show more than a straight face.

“I actually really don’t smile for pictures or nothing,” Cook admitted as a grin started to creep on his face. “I don’t know why. I’ve got nice teeth, but I don’t know why I don’t smile. That’s just being me.”

“It’s going to be a great day when you get him smiling because he don’t show no emotions so you never know what’s going on,” Bills defensive lineman Shaq Lawson joked, who is also someone Cook named among the teammates he’s most comfortable with. “You seen it on Sunday, he had a smile on his face. I seen him with a big smile.”

Sunday’s smile is just an example of the difference from Cook between the lines and outside of them.

“When I’m on the field I’m a different person,” Cook said. “I think I open up more on because why not? Other than that I’m just chill.”

Chill is anything but Cook’s approach when he gets the ball in his hands.

“My first mindset is to put the ball in the end zone,” Cook said. “Then my second mindset is to kill my defender in front of me. That’s my mindset.”

Until he’s out of the pads.

Then it’s back to being quiet James Cook.