Andrew Knapp was weeks from starting his freshman year of college when he joined Rhys Hoskins in the summer of 2010 on a Northern California travel team.

They played a couple of games together the previous summer, but this was their first true experience as teammates. Hoskins and Knapp, who played at different high schools outside of Sacramento, joined other premier players from their area on the El Dorado Hills Vipers to play teams up and down the coast.

It was a chance for them to gain experience as their baseball careers were starting to become more intense. Knapp moved in that August to his dorm room at the University of California and was drafted three years later by the Phillies. Hoskins had one more year of high school ball to play before spending three seasons at Sacramento State and being drafted by the Phillies in 2014.

“He always raked,” Knapp said. “A big body, super nice and just loved baseball. Same guy. Nothing’s changed really.”

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That summer with the Vipers also provides Knapp with the perspective to understand what the Phillies will miss as Hoskins, 28, undergoes season-ending abdominal surgery with just five weeks remaining in the season. The Phillies will miss more than just Hoskins’ power bat and his team-leading 27 home runs while they try to chase down a postseason berth. And the player he teamed with as a teenager knows best.

“It’s pretty obvious in the lineup what he brings, but just having him out there every day, he’s definitely one of the leaders in that clubhouse,” Knapp said. “All he wants to do is win and go out and play the best he can. He wears his emotions on his sleeve. If we’re not doing good, he’s in a bad mood. ... He’s embraced this city and they’ve embraced him.

“He’s that guy for us. He holds people accountable, and he goes out and posts every single day.”

The Phillies will be hard-pressed to replace Hoskins’ production in the lineup — he led the majors in slugging percentage in the second half before his season was finished. A torrid finish by hitters such as Bryce Harper and J.T. Realmuto could help the offense mask Hoskins’ absence, but it will be even harder to replace the things he does off the field.

“Not having his bat is huge, but also not having the leadership,” Realmuto said. “He’s still going to be here with us, but it’s not the same not having him in the lineup, not having him in the field. It’s a tough loss, but the rest of us have to pick up the slack and we have to play better. Every team goes through injuries. Every team loses players. It’s not an excuse for us. The guys who are on the field have to play better and pick up the slack for him.”

It’s been five seasons since Hoskins reached the majors and he has spent nearly every day of his career as one of the leading faces of the team. Tough question? Hoskins steps up to answer it. Community event? Hoskins is there. Clubhouse message? That’s usually Hoskins, too. It’s been that way since he first stepped into the clubhouse in August 2017.

That leadership helped push the Phillies into playoff contention the last three seasons, but each September ended with disappointment. If the Phillies can finally break through, they’ll have to do it without the player who often guides them.

“He’s going to be around as much as he can, I can tell you that. He was screaming from the top step [of the dugout] all day [Thursday],” manager Joe Girardi said Friday. “He means a lot on and off the field. Rhys does whatever it takes to be successful. Rhys is a winner, for me. He leads by example. He’s great to have.”

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Before his season was shut down, Hoskins provided one final example when he returned from the injured list last week and homered three times in three games despite still being hobbled with a groin injury and an abdominal tear.

“I think every guy on this team is willing to put his body on the line. You say that, but once it happens, to go out and produce the way he did was really impressive,” Knapp said. “I think if there was any chance of him being able to play still, he’d be out here. It’s just not realistic.”

Girardi said it was “absolutely incredible” that Hoskins was able to play with his injuries. For Knapp, what Hoskins did was impressive, but it wasn’t hard to believe. This was the same guy he knew when he was a teenager.

“It’s because of the fight in him,” Girardi said. “Rhys is a really nice guy, but he has a lot of tough fight in him that you don’t necessarily see all the time, but it’s there all the time.”

Said Knapp: “It’s definitely going to hurt not having him on the field, but even if he’s in the dugout, that presence will be there. We’re going to have to find a way to battle through that and bring some energy that he brings.”