DeGrom has been on the injured list since May 11 with tightness in his right side and lower back.
The right-hander made one rehab start for the Mets' low Class A affiliate on Thursday, striking out eight without allowing a walk in three scoreless innings.
DeGrom threw a side session Sunday.
"Everything looked good,'' Mets manager Luis Rojas said before his team's game in Miami. "We're still going to monitor the rest of today and tomorrow, but he is on track.''
DeGrom, a two-time Cy Young Award winner, is 3-2 with a 0.68 ERA in six starts for New York this season with 65 strikeouts and seven walks in 40 innings.
After a seven-game winning streak, the Mets have lost five of their last eight entering Sunday's series finale in Miami. Following an off day Monday, deGrom and the Mets will face the Colorado Rockies to open a seven-game homestand.
ESPN's Bradford Doolittle and The Associated Press contributed to this report.