The Mets' 26-year-old right-hander will be dispatched to New York for an examination with team doctors on Monday.
DeGrom said he does not believe the issue is concerning.
"I'm calm about it," he said. "I don't think it's anything serious. I can probably go out there and pitch with it right now, but I think just talking to them, at this time of the year, it's not really worth pushing it. If I can skip one [start] and be 100 percent and let it calm down, I think that's what they kind of talked about."
DeGrom indicated he felt soreness at the top of the shoulder Friday, the day after facing the Nationals in D.C., then again Saturday throwing on flat ground.
"I just felt a little something after the last start and gave them a heads up. So they said let's just try to skip one and go from there," deGrom said. "I haven't felt anything all year. I think it's a little inflamed or something. I think I'll be fine."
Assistant general manager John Ricco said it is unclear whether deGrom will miss one or multiple starts until after Monday's medical examination.
Rafael Montero is due to be called up from Triple-A Las Vegas to fill in for deGrom, a source confirmed to ESPNNewYork.com.
Montero told Dominican journalist Hector Gomez in Spanish: "I'm coming off two very good starts. I feel like I'm in my best physical form of the whole year."
The Mets are not prepared to announce the decision until deGrom is examined in New York later Monday.
Daisuke Matsuzaka (elbow inflammation) already is eligible to return from the disabled list, but was not a consideration to fill in Tuesday because he first needs to make a rehab appearance, which is scheduled to come Monday with Class A St. Lucie.
Ricco said having deGrom skip a start at some point this season was planned anyway. General manager Sandy Alderson has said the Mets plan to cap deGrom's workload at 185 innings this season. DeGrom currently is at 138 2/3 innings between the majors and minors. If his workload continued uninterrupted for the remainder of the season including Tuesday, deGrom would have made eight more starts.
DeGrom is 6-5 with a 2.87 ERA in 16 major league starts this season. He went 4-1 with a 1.39 ERA in five starts in July to earn the NL Rookie of the Month award.
DeGrom said he had shoulder soreness last season as well.
"Last year it was in a different spot," he said. "I haven't had this. Talking to the guys, they don't think it's anything serious."