But he certainly looked healthy.
"I was nervous, to be honest with you," deGrom said after firing two innings of one-hit ball Tuesday night in New York's 2-0 victory over the Houston Astros.
"First time facing another team -- you know, [when] you face your guys it's more relaxed, more fun -- but you get out there with guys in another uniform, I was a little nervous."
The two-time Cy Young Award winner got off to a sensational start last season, going 7-2 with a 1.08 ERA over 15 outings. But an elbow injury sidelined him the entire second half of the season, and the Mets collapsed without him after leading the NL East for a long stretch. The right-hander's last start was a seven-inning effort against Milwaukee on July 7.
It took a while for the inflammation to subside, but deGrom eventually started to feel better and his elbow was deemed healthy. He was ramping up his throwing when the Mets -- out of the playoff picture -- shut him down for good on Sept. 28 with a few days left in the season.
"The main thing I worked on in the offseason that carried over today was being really smooth down the mound," deGrom said of his 30-pitch outing, which featured 24 strikes. "Everything felt good. It felt like I was in sync."
The 33-year-old deGrom blew away the Astros with three strikeouts in a 15-pitch first inning, fanning two swinging and one looking. He topped out at 99 mph on one delivery but hit 98 mph on every other fastball as he brought the heat early.
"I was letting it go the other day against our guys," deGrom said. "It's reassuring to go out there and feel completely fine."
For the first time with the Mets, new manager Buck Showalter viewed deGrom from the dugout, saying: "He's pretty good. Just the health and freeness is what you're looking for and then tomorrow how he feels."
Hall of Fame catcher Mike Piazza, one of two guest instructors in camp this week along with former outfielder Mookie Wilson, said having a pair of multiple Cy Young Award winners like deGrom and Max Scherzer at the top of the rotation is a fine start.
"Ultimately [with] your ace, you expect to go out and win that night, have a better than average chance of winning," Piazza said. "When you have those downs, those tough times during the season, those are the guys that can stop an extended slide.
"The best teams are the ones who stop those slides quicker."
Showalter gave some good news on the injury front, telling reporters that new outfielder Starling Marte (left oblique) hit off a tee Monday with no discomfort. He will play defense in a minor-league game Wednesday as he gets closer to real action.
The Associated Press contributed to this report.