Angels closer Jordan Walden is feeling the effects of long season

Reporting from Seattle -- Angels rookie closer Jordan Walden was an All-Star in the first half of the season but has had his struggles lately, blowing two of his last four save opportunities and retiring only one of four batters in his most recent outing, Saturday in Texas.

In only his second year as a reliever, Walden is on pace to pitch in 63 games. And the additional wear and tear, he said, may have something to do with his recent slump.

“It’s getting close to September. And I’ve never thrown this much in my whole life,” he said. “It’s different. Your body, you just get tired.”

Walden leads the majors with nine blown saves in 35 chances. And though he has pitched in only 13 games in the second half, opponents are hitting .283 against him, 77 points higher than in the first half.

“He’s had a lot of success this year and there have been some [games] that slipped through the cracks,” Manager Mike Scioscia said. “It’s all part of the process of developing a closer. There’s a learning curve. And Jordan’s going through that process right now.

“That’s doesn’t mean he’s not going to get it done and be effective. But it does mean that at times there’s going to be little bumps in the road. And we’ve had some of them.”

Sweet homecoming

Joel Pineiro started his big league career in Seattle and he left more than just fond memories behind when he departed.

“A lot of people. A lot of friends,” he said. “My baby’s godparents are there.”

Which may explain why he feels so comfortable pitching there. Over the last seven weeks, opponents had hit .382 against Pineiro, who was 0-3 with a 10.21 earned-run average during that span. But back in Seattle on Monday, he turned in his best performance of the second half, giving up three runs and seven hits in six innings.

The Angels hope that’s something Pineiro can build on going forward, but unfortunately the team doesn’t return to Seattle this season.

“There’s some ballparks — whether it’s the visual, whether it’s just the dimensions, the infield grass — where there are things that affect the pitcher’s comfort level,” Scioscia said. “Some guys actually feel at home in certain parks. There is a comfort level that develops.”

Jepsen to have surgery

Scioscia said the Angels will call up some much-needed bullpen help when rosters expand to 40 players Thursday, with right-hander Michael Kohn and left-hander Horacio Ramirez among those likely to be summoned. One pitcher who won’t be called up, though, is right-hander Kevin Jepsen. Team orthopedist Lewis Yocum will perform arthroscopic surgery Wednesday to clean up Jepsen’s right knee, ending his season.

Jepsen, who had a 3.97 ERA in 68 games for the Angels last season, sprained the knee pitching for triple-A Salt Lake last month. Doctors said there were no torn ligaments, so Jepsen will need only six to eight weeks of rehabilitation after the procedure.

Weaver’s contract terms

The five-year, $85-million contract Jered Weaver signed last week includes a full no-trade clause, a $1-million signing bonus and an annual salary that will make the right-hander the Angels’ highest-paid pitcher next season.

Weaver will earn a base salary of $14 million in 2012 and $16 million in each 2013 and 2014. His salary will jump to $18 million in 2015 and $20 million in 2016, the final year of the contract.

kevin.baxter@latimes.com