The right-hander was hit hard by the Mets for five runs over 2 2/3 innings on Tuesday to finish his Grapefruit League season with an 8.02 ERA over 22 1/3 innings.
"Today was one of the worst days of my life," Nova said. "I wasn't pitching right. I felt good today but I couldn't throw strikes."
Nova won 16 games last season but has struggled mightily this spring. The 25-year-old says he feels fine physically, but admitted his body was "lazy" on Tuesday.
"Lazy, like arm lazy and body lazy," Nova said. "You cannot extend your arm. You're cutting yourself short. My body feels like it was sleeping or something like that."
The right-hander is scheduled to make his regular-season debut on April 9 against the Orioles. Until then, he will be working on improving his fastball command.
"I've got to keep working the same on everything that I was working on," Nova said. "I need to work on getting my fastball back, the location on it. When I get my fastball command, all my other pitches are easier. I've got to work at it and get my command of my fastball."
Manager Joe Girardi agrees that Nova is at his best when he can command his fastball. He has seen flashes of that command at times this spring, but he would like to see more from the young starter.
"I feel like he's had some really good innings, but he's kind of lost a little bit of command at times," Girardi said. "That's something that you have to be able to control a bit quicker. Sometimes you get back to it by throwing different pitches. Sometimes you should start guys with breaking balls. He's been inconsistent this spring, but I really feel the stuff is there."
With no more Spring Training starts scheduled, Nova is looking forward to putting the past month behind him and focusing on what he hopes will be another positive season in the Majors.
"Spring Training just ended for me right now, so I'm just going to look forward to the season," Nova said. "Maybe all the bad little moments happened here in Spring Training, and I'll have a good season again. That's what I'm looking for."