Feliciano threw one inning against the Miami Marlins in a "B" game on a practice field behind Roger Dean Stadium. He allowed one run -- on Ben Lasater's home run -- hit a batter and struck out one.
"I think it was better than what I was expecting in my velocity, release," Feliciano said.
Feliciano was diagnosed last week with a rare genetic condition called left ventricular noncompaction. The condition results from the failure of myocardial development from birth. Feliciano said he never thought about the heart monitor while in the game.
The 36-year-old left-hander, who missed the past two seasons because of a shoulder injury, threw 11 of 18 pitches for strikes. His fastball was clocked by scouts in the low 80 mph range.
Mets starter Shaun Marcum, who has not pitched in a regular exhibition game since the opener on Feb. 23, loaded the bases on two hits and a walk with one out in the first, then retired five in a row.
"I still feel like I'm pushing some with my fastball," he said. "The changeup was a lot better today. I didn't leave any of those up. I had good depth on them. I still don't feel 100 percent with my mechanics yet. I feel like I'm rushing on some fastballs"
Mets pitching prospect Jenrry Mejia was scratched due to an undisclosed medical issue. He returned to New York to undergo tests relating to his physical.
Marlins starter Jacob Turner threw two scoreless innings, allowing just two walks and striking out one.