There are no excuses. No one holds him more accountable than himself. And he remains relentlessly positive in his quest for his first Super Bowl championship.
This comes in the wake of a play Sanu would like to have back from Saturday's 24-17 win against the Buffalo Bills: a fourth-and-1 run for no gain by fellow receiver N'Keal Harry during which Sanu was supposed to be paving the way as a lead blocker. The miscue near the end of the second quarter was a catalyst for the Bills to get back in the game.
"It was me, more than anything, trying to see if we were about to change a play or not. Then the ball was snapped and I was [surprised]," he explained of the play in which Bills cornerback Kevin Johnson was initially up on him before surging past him to the outside to tackle Harry. "I take full responsibility."
The play reflects, in part, how Sanu has been navigating a challenging transition: Traded to the Patriots on Oct. 23, he has been thrown into a completely new offensive system, with high expectations because the club dealt a second-round draft choice for him.
He's naturally not as comfortable as he was with the Cincinnati Bengals (2012-15) or Atlanta Falcons (2016-19), when his mastery of the offense allowed him to play free. That was a point sixth-year running back James White made this week when asked what has stood out to him about Sanu.
"The week he came in, we were doing no-huddle, so that was even more difficult. I couldn't imagine," White said.
Still, Sanu started fast with 10 receptions in his second game, a loss to the Baltimore Ravens. The production has dipped significantly since he sprained his ankle against the Philadelphia Eagles in the following game. Having played in seven games with New England, Sanu enters Sunday's regular-season finale against the Miami Dolphins (1 p.m. ET, CBS) with 23 receptions for 172 yards (7.5 average) and one touchdown.
That falls short of what Emmanuel Sanders (33 catches, 477 yards, 3 TDs) has produced in nine games since being traded to the San Francisco 49ers. Sanders did, however, have the advantage of having a background in the 49ers' offensive system, which had significant crossover to where he was coming from in Denver.
Sanu, 30, hasn't had that luxury, but he isn't making excuses.
"I haven't really scratched the surface yet of what I know I can do," he said. "Getting adjusted to things people have known for years, or months, you have to catch up. It's a lot of little details of things. I've been getting right up to speed. It's just little things you can't teach; they just have to be done. It's the difference between knowing and doing."
One such example of that came in a win against the Bengals on Dec. 15. Sanu was the intended target on a fourth-down pass from quarterback Tom Brady, and the football got to him much faster than he anticipated and went through his hands.
Or other times, such as a 4-yard catch on a third-and-5 play against the Bills on Saturday, when the tempo and precision of his out-breaking route were just a bit off from where he wanted it.
Sanu has nonetheless remained upbeat, knowing there is high-stakes football ahead. How hungry is he to contribute to the Patriots?
"You have no idea. It's not something you can explain," he said. "You put a lot of work into something, a lot of time, a lot of sacrifices, and the time you put in, you want the same result from it."
Players and coaches are confident it will pay off for Sanu.
"He's one of the hardest-working guys I've been around," said safety Devin McCourty, whose connection to Sanu traces to when they were teammates at Rutgers. "He's played in big games and done it before. It's always unique when you get a guy in here who is a leader type of guy, who comes in with experience from other teams, and you can tell those stories to other guys. He also brings that."
McCourty added that Sanu's toughness as a bigger receiver (6-foot-2, 210 pounds) -- and his willingness to "do the dirty work" -- has fit well in New England. Over the past two weeks, as the offense has found a more consistent groove, that has shown up at times, as Sanu has been part of more two-receiver sets with Julian Edelman.
"Our system is different than the ones he's played in before, so he's done a great job of trying to acclimate to what that terminology is and what his role is each week. He is still continuing to grow in our foundation," offensive coordinator Josh McDaniels said.
"I'm happy with what he's doing, the direction we're headed, and the progress hopefully we can continue to make with him. That's a big thing for us moving forward."