PHILADELPHIA -- Phillies left fielder Brandon Marsh experienced pain and swelling in his left knee early this week, so he flew to Philadelphia to have a team physician take a look.

The team announced on Friday morning that Marsh had “successful” arthroscopic debridement surgery. He is expected to return to action in three to four weeks.

“Oh, we think he’ll be ready to play for sure on Opening Day,” Phillies president of baseball operations Dave Dombrowski said Friday from Clearwater, Fla. “It’s not a new injury. It’s something that just bothered him when he was working out. They basically found a floating piece of cartilage. It’s old. It’s been in there. All of a sudden, it moved to a different place to a joint area that bothered him. It’s not something that happened this week, but it’s something he first experienced the pain this week.”

Dombrowski said Marsh’s surgery does not increase the front office’s urgency to acquire more outfield depth, although that could change. Right now, it projects its Opening Day outfield to be Nick Castellanos, Johan Rojas and Marsh, with Cristian Pache and Jake Cave as the fourth and fifth outfielders.

The Phillies on Wednesday designated outfielder Símon Muzziotti, after they knew about Marsh’s knee issue, which seems to back up their belief that Marsh will be ready by Opening Day. The only other outfielder on the 40-man roster is Kyle Schwarber, who is expected to be the primary designated hitter. Dombrowski mentioned non-roster invitee Cal Stevenson as potential outfield depth. He has spent time in the Majors the past two seasons.

“We still think we’re the same way we were beforehand, when it comes to Opening Day,” Dombrowski said. “[Free-agent outfielders] want guarantees, and we’re just not able to give them those guarantees. … We talk to people all the time. The reality is that we don’t have guaranteed playing time that some people want. We just don’t have that. It’s not really even a dollar issue as it is playing time.”

The Phillies continue to be linked to big-time free agents like outfielder Cody Bellinger and starting pitchers Blake Snell and Jordan Montgomery. Sources said earlier this week that unless the market changes drastically in the coming weeks, they do not expect to sign one of those players, although the Phillies would like Montgomery on a 1-3 year deal.

There was another report this week that the Phillies have been talking to Cleveland about closer Emmanuel Clase. Dombrowski does not comment on specific trade talks with teams, but when asked about the chances they acquire a veteran late-inning reliever, he said, “We do not have any ongoing conversations for bullpen guys.

“It’s not to say that as time goes on it doesn’t change, but we have our five guys [José Alvarado, Seranthony Domínguez, Jeff Hoffman, Gregory Soto and Matt Strahm] and [Orion] Kerkering. I just saw him. He looks tremendous. If you put those six guys that can pitch late in the game, you have to have a long guy. That’s seven [in the bullpen]. It only leaves one other spot, and if you go get a veteran guy, he needs to be an upgrade. Because the reality is the only one there that can be optioned in that group is Kerkering. And we may not want to be optioning him.”

Still, the speculation about the Phillies going big will continue until every last big free agent is signed.

“There are different ways to build ballclubs,” Dombrowski said. “We have a lot of veteran, good players. To me, it’s good to combine some young players in there. We’ll see what happens with Rojas and [Cristopher] Sánchez and Kerkering. But we’re really thrilled about giving them the opportunity and mixing them in, because we think they have a lot of ability. Now, are they ready to grab onto it right now? We’ll find out, but we’re excited about the opportunity.”