Sean Rosenthal and Phil Dalhausser try to find a rhythm

They’re known as “Rosie’s Raiders,” a group of friends and fans who follow Sean Rosenthal and heckle opponents.

A cowbell-toting collection of them showed up at the Long Beach Grand Slam to cheer on Rosenthal and partner Phil Dalhausser.

At the Manhattan Beach Open, however, the group was smaller and quieter than usual.

Maybe the Raiders needed a break, like Dalhausser and Rosenthal themselves. The pair did not play in last weekend’s AVP tournament in Salt Lake City.

Dalhausser is nursing a minor but nagging abdominal injury. After giving himself a rest, he is ready to play through it.

“I thought maybe I caught it early enough in Salt Lake — take Salt Lake off, and maybe it’ll heal 100%, but it hasn’t,” Dalhausser said. “So I just have to deal with it for the rest of the season, six more tournaments left.”

The injury is a tricky one, particularly during a grueling season that doesn’t give players much planned time off.

“You do everything with your abs,” Dalhausser said. “It’s hard to heal it quickly because you’re constantly aggravating it, especially in volleyball. … When you’re hitting or setting or blocking, you extend your stomach.”

The FIVB and AVP tournaments run concurrently, so many American players alternate between international and domestic tournaments.

Most recently, in back-to-back-to-back weekends, Dalhausser and Rosenthal shuttled between the U.S. and Europe, visiting the Hague, Long Beach and Klagenfurt, Austria.

Dalhausser said he had spent almost the last eight weeks away from home, so the short break he and Rosenthal did get was most welcome.

“[Dalhausser] asked me if I was going to pick someone up and go out there [to Salt Lake City], and I was like, ‘No way,’” Rosenthal said. “I just knew, the week off — it’s good for the body but also for the mind too.

They didn’t play their crispest volleyball after the brief hiatus, but they got it done Friday on the first day of main draw competition in Manhattan Beach. They won their first match efficiently: 21-8, 21-13 in 33 minutes.

In their second match, they played Jason Lochhead and Russ Marchewka, who advanced to the main draw out of qualifiers. Dalhausser and Rosenthal won in straight sets again, 21-17, 21-17, but Lochhead and Marchewka kept them from establishing a consistent rhythm.

“We won ugly,” Dalhausser said. “But I’ll take a ‘W’ any which way it comes. We missed a lot of serves, and when you miss serves, it’s just free points. We didn’t really side out too well. It was just sloppy, ugly volleyball.”

They did just enough Friday but can’t ride performances like that if they hope to win tournaments, Rosenthal said.

“We have to play better than that to continue to win out here,” he said.

Dalhausser and Rosenthal have yet to win on the AVP tour this season. They placed third at the season opener in St. Petersburg and second in Milwaukee the first weekend of July.

On the FIVB tour, however, Dalhausser and Rosenthal rank first, ahead of Brazil’s Alison Cerutti and Bruno Oscar Schmidt by 350 points. A Grand Slam victory is worth 400 points.

From June 25 to July 13, Dalhausser and Rosenthal won back-to-back Grand Slams in Stavanger, Norway, and Gstaad, Switzerland. They also won the Long Beach Grand Slam, held at the end of July.

But this is only the second season together for Dalhausser and Rosenthal. Both played on the left side throughout their careers with other partners, and Rosenthal made the move over to the other side this season after Dalhausser tried the shift last year.

“I don’t think we’re anywhere really close to where we want to be,” Rosenthal said. “It’s my first year on the right. We’ve definitely had a good year, but I know every tournament, every game I play, it’s just going to help me see the court better. …We’re definitely going to get a lot better.”

Dalhausser and Rosenthal play Nick Lucena and Ryan Doherty on Saturday at 12:20 p.m.