X-rays were negative, but Harper said after the game that he could not grip a bat, and he was not in the lineup Saturday.
"I don't know yet. See tomorrow how I feel," he said on Friday night. "Of course, we're in the stretch right now, so if I can be in there, I'm gonna be in there. But gotta be careful too."
Harper, batting with one out and a runner on third, was ahead in the count 1-0 when Matz's 93 mph fastball sailed up and in on him. Harper recoiled and the ball ricocheted off his hand.
The 26-year-old fell to his knees and gripped his hand in pain before getting to his feet and walking back to the plate, where Mets catcher Wilson Ramos appeared to ask Harper how he was doing. Harper put his head on Ramos' shoulder before Ramos, a former teammate with the Washington Nationals, patted him on the shoulder.
After a brief visit from a trainer and manager Gabe Kapler, Harper trotted to first base. He was retired at second on an inning-ending double play by Rhys Hoskins, after which Sean Rodriguez trotted out to replace Harper in right field.
"Any time it squares you up a little bit, it's scary," Harper said. "Definitely wanted to get on first and keep the game going. But yeah, it wasn't good."
Harper's plunking might be the latest chapter in what has become a volatile rivalry this season. The Mets have been hit by a pitch 14 times in 16 games against the Phillies, who have been hit by a New York pitcher eight times.
Hoskins took offense to a pair of up-and-in pitches from Jacob Rhame on April 23 and punctuated his displeasure by taking a 35-second home run trot after going deep off Rhame the next night.
On July 6, Phillies right-hander Jake Arrieta hit three Mets batters. Todd Frazier, the second batter plunked by Arrieta, was ejected for arguing after home plate umpire Tripp Gibson warned both teams. Two batters later, Arrieta wasn't ejected after hitting Amed Rosario with a changeup, though New York manager Mickey Callaway was tossed for arguing. After the game, Arrieta said if Frazier was unhappy about being hit, "he can come see me and I'll put a dent in his skull."
Harper, in the first year of a 13-year contract worth $330 million, is batting .254 with 30 homers and 100 RBIs in 136 games.
Information from The Associated Press was used in this report.
Harper hit on hand by pitch
Bryce Harper is hit in the hands by a Steven Matz pitch and would have to leave the game in the third inning.