The Phillies announced that the reigning National League MVP will be out indefinitely. He will undergo further evaluation in the next few days.
"I've never had a hand injury like this," Harper, who was wearing a splint on the injured thumb, said Saturday. "Never broken anything in my life. This is new to me, so I'm just going to go day by day, see kind of where we're at and see the specialist in Philly. And if I do need to see another specialist somewhere, then I will."
Harper checked his swing as the pitch from Snell rode inside and high before hitting him on the outside of the left hand. Harper immediately fell to the ground and was in visible pain as he held the hand while on his knees for several minutes with Phillies head trainer Paul Buchheit attending to him.
"I kind of wish it would've hit me in the face. I don't break bones in my face," Harper said with a laugh. "I can take 98 to the face, but I can't take 97 to the thumb. Yeah, I was kind of in protection mode a little bit trying to get my hand up there and not let it hit me again.
"It's just a bummer. I am really bummed out."
He was officially placed on the 10-day injured list on Sunday. Outfielder Mickey Moniak was recalled from Triple-A Lehigh Valley in a corresponding move.
Phillies general manager Dave Dombrowski, who traveled with the team on the road trip, said Saturday that it was too early to determine whether surgery will be needed. He added that he wasn't sure what type of fracture Harper had or where on his left thumb the injury occurred.
As Harper was halfway to Philadelphia's dugout, he angrily yelled at Snell and motioned with a hand at the Padres' starting pitcher. Snell eventually shouted back at Harper. Many fans at Petco Park fans started to boo after several seconds of Harper shouting at Snell.
Harper then appeared to cool down and say, "I know, I know," to Snell, acknowledging that the pitcher didn't mean to hit him with the pitch.
"It wasn't heated at all," Harper said. "It was just the moment and a crappy situation. I've been playing against Blake since we were 10, 11 years old, so I know there was no ill will behind that at all. The inside pitch is part of the game. He is a great player and a great human being as well. I wish him the best, and I told him to keep throwing that inside fastball because it sets that slider really good."
Snell texted Harper and said the two are on good terms.
"Obviously, I felt terrible hitting him," Snell said Saturday. "I don't do that, and he knows that. We've talked. We've handled it. He plays with a lot of passion, and I can understand why he'd be upset. I'm just as upset as he is. ... I just hope he recovers quickly and gets back out there and continues to compete."
Snell added that he and Harper were going to see each other after Saturday's game or on Sunday.
"He is a guy who really isn't replaceable on an individual basis, but we are going to have to be in a position that other people are going to have to step up," Dombrowski said. "We will make a move to try and get someone here [Sunday]."
Harper is hitting .318 with 15 home runs, 48 RBIs and a .985 OPS this season in 64 games despite a small tear in the UCL of his right elbow that has prevented him from playing the outfield since April 16. He has tried to avoid season-ending Tommy John surgery with a platelet-rich plasma injection and rest.
"I don't know how long he is going to be out at this point," Dombrowski said. "I am hopeful he will be back at some point. We still have a lot of good hitters in the lineup. ... The Braves won the World Series last year without [Ronald] Acuna."
The Associated Press contributed to this report.