DeGrom, sidelined since last July 7, threw 27 pitches to hitters in Port St. Lucie, Florida, and could progress to a minor league injury rehabilitation assignment.
"We'll see how he feels tomorrow," Mets manager Buck Showalter said after watching on video from Citi Field. "Tomorrow, if he feels well, we'll probably be able to talk about that next step."
A two-time Cy Young Award winner, the 34-year-old right-hander missed the second half of last season because of right forearm tightness. He returned and made spring training starts on March 22 and 27, then was sidelined by a stress reaction in his right scapula that caused inflammation. He did not throw another bullpen session until June 4.
"He hasn't had anything that has taken him off schedule so far," Showalter said. "You can tell he's upbeat about where he is. The body language, more than anything."
Scherzer, a three-time Cy Young Award winner, has been sidelined since straining his left oblique muscle while pitching against St. Louis on May 18. He made his second rehab start for the Double-A Binghamton Rumble Ponies on Wednesday night, taking the mound against the Hartford Yard Goats.
Scherzer allowed three runs (two earned) in 4 2/3 innings, striking out eight and walking one before he was relieved. He threw 80 pitches, including 57 strikes.
"I was going to send him a 'good luck with the Yard Goats,' but I don't think he'd take it well," Showalter said. "I think I will anyway."
Scherzer threw 65 pitches for Binghamton against Reading on June 21, allowing two runs and three hits in 3⅓ innings with six strikeouts and a walk.
After agreeing to a $130 million, three-year contract, baseball's highest average salary, Scherzer is 6-2 with a 2.54 ERA in eight starts.
The Associated Press contributed to this report.