By the time fans entered the stadium Friday night, the No. 21 memorabilia had been removed from the team stores, the Austin Hays posters torn down and the locker that once belonged to the left fielder reassigned to Heston Kjerstad.

In a matter of hours, all visible traces of Hays were gone at Oriole Park at Camden Yards. A key member of the rebuild, one of just four to survive from start to finish, was traded to the Phillies on Friday afternoon for reliever Seranthony Domínguez and outfielder Cristian Pache.

The Orioles needed a reliever. And, to get one, they parted with a guy who once meant so much to the team. This hasn’t been his best season — he went on a 1-for-33 stretch in April — but he has been performing better the last two months, even as his playing time has dropped due to young prospects.

“I have so much respect for him,” manager Brandon Hyde said. “Nobody played harder. Nobody played more hurt. ... He just is a true pro, so to lose someone like that who we’re all close to, it’s tough. It’s tough. He’s a close friend for a lot of guys in that clubhouse.”

On Friday night, Kjerstad stood in Hays’ place in left field as the Padres beat the Orioles 6-4 to open the three-game series, with Colton Cowser in center field and Anthony Santander in right. Domínguez and Pache, after making the short drive from Philadelphia, sat in the dugout, clad in the black City Connect uniform, as they watched their new team. Other newcomer Zach Eflin, acquired from the Rays on Friday, is expected to join them this weekend.

Although the physical traces of Hays are gone, it will take far longer for the impact Hays left on the dugout to be erased. He was a leader in the clubhouse, an ear for all and a mentor for the next generation.

“He’s not a guy who is easy to replace,” Dean Kremer, who had played with Hays since he was traded to the Orioles in 2018, said. “It doesn’t matter what day it is, what time the game is, it doesn’t matter anything like that, he’s a blue-collar hard worker. He gives it everything. He’s just one of the best teammates I’ve ever been around.”

By this time next year — perhaps even this time next week as Tuesday’s trade deadline looms — there could be only one member of the rebuild left. Santander and John Means will be free agents next year. Cedric Mullins, who has one more year of control, has been grouped into trade rumors, although the Hays trade may mean that he is now safe.

The team was always going to have to move on. It just may not have expected it to happen so soon.

“I’m sad to see him go, but I’m happy for him,” Jordan Westburg said. “It’s a new opportunity. It’s a fresh start for him. Hopefully, he can impact that team well and we can match up in the World Series.”

With Hays gone, there could be an opportunity for Kjerstad to get daily playing time. His defense has always been a weaker spot for him, and left field at Camden Yards can be tricky. It got the best of him Friday. In the sixth inning, with the game tied 2-2, Kjerstad ran his route to chase down a fly ball from Xander Bogaerts.

The ball landed in Kjerstad’s glove, but he couldn’t secure it and the Padres scored to take the lead.

“It’s a long way to go,” Hyde said. “I don’t know if he got turned around a little bit, but there’s a lot to deal with there. You’re not used to running that far back behind you and then with the wall, track, I can’t answer for him, it just looked like he got caught up a little bit. He almost made the play, but a tough play.”

The play, according to Statcast, had a 99% catch probability. Would Hays have made that play? There’s no way to say for sure, but the likely answer, given his track record, is yes.

A batter later, Severna Park native Jackson Merrill sent another ball Kjerstad’s way. This one was harder to track down, the ball landing near the foul line, and the Padres sent in another run to extend their lead to 4-2.

In the eighth, just nine hours after he was acquired, the Orioles got their first glimpse at their Domínguez. His fastball touching 99.3 mph as he worked a scoreless inning.

Pache got his turn in the bottom of the inning. After Santander homered to get the Orioles within one, Ryan O’Hearn doubled and Kjerstad hit a bloop single, Pache taking over as the pinch runner.

The Orioles tied the game on a Ryan Mountcastle sacrifice fly, then Pache advanced to third on a Cowser single, but he was stranded there as Mullins struck out to end the inning.

There wouldn’t be a comeback to end the emotional day. Craig Kimbrel, a day after surrendering a three-run lead in Miami, gave up a two-run home run to Jurickson Profar, who did the griddy as he reached home plate in celebration of the Padres’ eventual win.

“I mean, just the last two days I haven’t gone out there and done my job,” Kimbrel said. “I let the team down. And I’m really disappointed in that. We played a good game today. Fought back in it. Made it close. My job [is] to come in there and keep it rolling, keep it exciting. I wasn’t able to do that.”

After the game, there was disappointment from the loss in the stadium but a different feeling in the basement of the stadium, where the players’ kids gather as they wait for their fathers to come out. Christian and Kane McCann, sons of catcher James McCann, felt sadness.

It’s not just Hays who was traded. His sons, Levi and Hayden, Christian and Kane McCann’s friends, were also gone.

“That’s something a lot of people don’t understand, those relationships that are built,” James McCann said.