"I just felt a little discomfort warming up, and after that I didn't have much on it," Martin said.
His fastball topped out at 85 m.p.h., well below his average of 93 last season when he sometimes lit up the radar gun at 96 m.p.h.
The Phillies said Martin would be examined by a doctor Friday.
"Obviously I'm concerned, no matter what happens," Martin said. "It's frustrating. I feel like I worked out and did everything I needed to do to prepare to get here, and this happens, so obviously it's frustrating."
A year ago, the Phillies thought they were well-equipped with pitching depth because they had Martin, Pettibone, and lefthander Adam Morgan, but all three of them have now experienced arm problems, which makes the emergence of Cuban righthander Miguel Alfredo Gonzalez even more important. There have, however, been concerns about the rookie Gonzalez, too.
"It's a concern to have a couple guys banged up a little bit with the starting pitching," manager Ryne Sandberg said. "[Cole] Hamels has come along fine, but it's just a concern with Ethan. But we'll just wait and see what turns up tomorrow after he gets checked out."
Mike Adams took another step in his comeback bid from the shoulder surgery that ended his 2013 season with the Phillies on June 19 last year.
After an uncomfortable session throwing from flat ground Monday at Bright House Field, the 35-year-old reliever admitted to being nervous even though he was going to do nothing more than throw off a mound in the bullpen Thursday morning.
"When you've been through what I've been through as far as injuries and shoulder stuff, any kind of discomfort gets in the back of your head," Adams said. "I talked to [trainer] Scott [Sheridan] the other day, and he's like: 'Hey, you've got every right to panic a little bit. What you've been through, it's normal.' "
Adams, considered one of the best setup men in baseball when he signed a two-year, $12 million deal with the Phillies before last season, has had his share of health issues in recent years. In addition to the shoulder surgery in late July, he also needed surgery to repair a sports hernia in October. The previous October, before signing with the Phillies, he had surgery for thoracic outlet syndrome, a nerve condition that impacted his performance during his final season with Texas.
"Before I came out here, I was nervous," Adams said. "I was worried. Everything is an unknown. I don't know how it's going to go. It seems like every time I'm going out there, I'm hoping for the best. I'm just trying to stay positive. Every pitch could be the last pitch."
As it turned out, his fears were unfounded.
"It went good - real good," he said. "It was probably an 85 percent bullpen or so. With it being the first one, I wasn't trying to let loose right off the bat. I wanted to make sure I got a good feel for throwing off the slope again and finding my arm slot."
If all continues to go well, Adams said, he will throw in a spring-training game in the middle of March.