Denver Broncos wide receiver Eric Decker has insisted that quarterback Peyton Manning's throws have "more zip" this off-season.

Manning's arm ability has been weakened in recent seasons having undergone surgery four times on his neck, but Decker said that things look to be improving with the 37-year-old.

"We worked out at Duke in March or April, and I definitely felt like he had more zip on the ball," Decker told the Denver Post.

"I think he's come back stronger."

Manning had a 68.6% throwing accuracy in his 16 games played last season.