PHILADELPHIA — Jacob deGrom, the Mets’ best pitcher, returned on Sunday from a short stint on the 10-day disabled list for a hyperextended throwing elbow. He didn’t make it to the second inning.

DeGrom almost pitched last Monday, before the Mets, who overhauled their medical practices in the off-season after another injury-plagued season, decided to be more cautious. That attitude guided the Mets (19-18) again on Sunday, when they pulled deGrom after just one laborious inning of a 4-2 loss to the Philadelphia Phillies.

“I was kind of surprised, honestly,” deGrom said. “I definitely would’ve liked to go back out there. The reasoning, I understand, but who wants to pitch one inning as a starter?”

While the Mets have been cautious with deGrom, they have allowed their most powerful hitter, left fielder Yoenis Cespedes, to play through right quadriceps discomfort. In the sixth inning, he smashed a solo home run, but he moved gingerly after beating out an infield hit and after catching a ball in the outfield.