Bill Barnwell and Dan Graziano dive into the numbers to explain why the Jets and the 49ers are likely to take a step forward this season. (2:42)

Why the Jets and 49ers are safe bets to improve this year (2:42)

FLORHAM PARK, N.J. -- The New York Jets haven't used a radar gun to clock Sam Darnold's fastball, but they believe his arm strength is better than a year ago.

"It's interesting because a lot of people in the spring were saying that to me, that it looked like he was throwing with a lot more velocity," coach Adam Gase said Monday.

Gase's frame of reference began in the spring because he coached the Miami Dolphins last season. From the day he was hired by the Jets, Gase has lauded all aspects of Darnold's game.

"I don't think I realized how strong his arm was," Gase said.

Darnold said improved mechanics and less wear-and-tear in the offseason have allowed him to throw with more zip than his rookie year. He did a lot of throwing last spring as he prepared for the draft, which the Jets suspect contributed to arm fatigue.

This offseason, Darnold stuck to a structured throwing regimen and focused on improving his hip flexibility, which often translates to better arm strength.

A boost of self-confidence has also helped.

"Yeah, it comes with confidence, the confidence of knowing I can go out there and do this," he said after practice. "It's not that I didn't know that last year. It's just that with this offense, I feel like I already know most of it, so I'm just going out there and spinning it.

"Last year, I still wasn't super comfortable with all of the guys, getting in the huddle, feeling timid. I wasn't really myself. I think this year, now that I'm stepping into that leadership role, I could, you could say, I'm definitely more comfortable and confident in myself."

Darnold's rookie numbers were mediocre. In 13 starts, he recorded 17 touchdown passes, 15 interceptions and a 57.7 completion percentage. His Total QBR (45.9) ranked 28th out of 33 qualifying quarterbacks, but his QBR over the final four weeks (79.3) was No. 1 in the NFL.

The Jets expect him to make a significant leap, especially with an improved supporting cast led by former All-Pro running back Le'Veon Bell.

Sam Darnold says improved mechanics and less wear-and-tear in the offseason have allowed him to throw with more zip than his rookie year. Photo by Joshua Sarner/Icon Sportswire

"It's easy for me to call plays," Gase said, referring to Darnold. "He's not the kind of quarterback you're looking to protect. You're looking to turn him loose. ... There are no limitations with him. That's fun as a play caller."

Running back Ty Montgomery, who spent three-plus seasons with the Green Bay Packers, said Darnold is similar to Aaron Rodgers in that he can make unorthodox throws.

"He's got that little whip he does," he said. "He can throw without his feet set ... and still throw an accurate ball downfield.

"He's got this, like ... if I played quarterback, I probably wouldn't be able to do it," Montgomery added. "But he's got this real quick flip. I've seen him throw the ball downfield. I've seen his feet set left and throw the ball right. He's talented, for sure."