Sanchez loads up on the head jokes, often poking fun at the size of the Jets' tight end's cranium. Keller reciprocates by playing the look-alikes game, offering up random pictures of people he thinks bear resemblance to his quarterback.
But it's all in good fun and a sign of their blossoming relationship, one that began in earnest in the spring of 2009. Keller took an immediate liking to Sanchez from the first time they started whipping the football around together on a field not far from the team's Florham Park, N.J., training complex.
The two have now become almost inseparable.
"They are always meeting extra together, they are always watching film together or always communicating," tight ends coach Mike Devlin said. "So I think that you-to-me factor is coming along nicely."
It all starts off the field, far from the coaches and the cameras. The duo enjoys spending time with each other, and that was evident when Sanchez attended Keller's offseason wedding, playing his average Joe role. But Sanchez needed a little assistance.
"We had to make sure we made announcements that nobody can be asked for autographs or anything like that," Keller said, "because Sanchez, he gets a lot of that all the time."
Keller should know, as much as he's out with the GQ cover boy. Whenever Sanchez is ready to hit Broadway and take in a show or has an inkling about grabbing a bite to eat, say in Manhattan, he typically will hurl an invitation Keller's way.
Keller usually does the same thing, leading to the mutual admiration they've acquired.
"He's one of those guys that you love to be around," Sanchez said. "He's got a great family, his brothers are around a lot. So, I know him really well off the field. That helps when you get on the field. We always know that even in those tough situations when we're upset at each other, or I miss a throw or he misses a catch, it's never personal. We're just trying to win, and it helps when you have that off-the-field chemistry, too."
Keller said: "A guy that you are comfortable with, you can say whatever you want. Whether you're mad at him, whether he did a good thing, you can say what's on your mind because he and I have that type of relationship.''
Keller, who led the Jets with 55 receptions in 2010 and established career highs in receiving yards (687) and touchdowns (five), has all the physical tools to rank among the NFL's elite tight ends. At 6-2, 248 pounds, he's a matchup nightmare, given he has good speed and quickness -- not to mention a vastly improved blocking technique.
Factor in those attributes with the continued rapport he's building with Sanchez, and Keller believes there's not a linebacker or defensive back who can check him one-on-one.
"Yeah, I definitely still feel that way," he said, "even more so now than ever because there's things I recognize now that I didn't before, and things I recognize faster than I did before -- certain coverages, how a guy is trying to play me, just the grand scheme of a whole entire play and what it's going to open up for me. I know if a ball is going to be coming to me before it actually is.
"I think it's just getting stronger and stronger the more I work with Mark."