Angels’ Scott Kazmir has been working on strength and flexibility

It wasn’t reflected in his earned run average -- 1.73 in six starts for the Angels after his Aug. 28 trade from Tampa Bay -- but Scott Kazmir did not think he was in peak form last season.

“I’d get nine or 10 pitches into an inning, and I didn’t have the explosiveness I wanted,” Kazmir said. “I was falling off pitches and stuff like that. At one point, you kind of wonder.”

So did Manager Mike Scioscia, who thought Kazmir’s stuff -- the left-hander has a 94-mph fastball and sharp slider -- was usually good, but his ability to put hitters away sometimes waned.

“His execution at times wasn’t where it needed to be, where he threw a lot of pitches trying to get to a certain point in the game,” Scioscia said. “When he’s right, he’s putting that good fastball where it needs to be, burying that slider.”

This was especially noticeable in Kazmir’s two playoff starts, when he gave up five runs in six innings in Game 3 of the American League division series against Boston and four runs in four innings in Game 4 of the American League Championship Series against New York. He needed 89 pitches to get through his last outing.

The slippage prompted a shift in Kazmir’s winter regimen. Working with Houston-based trainer Lee Fiocchi and fellow big leaguers James Loney, Carl Crawford and Adam Dunn, Kazmir focused more on strengthening his core and legs and improving his flexibility and range of motion.

Though he has been slowed early in camp by a minor hamstring injury and a sore throat and fever, Kazmir can feel a difference.

“I feel like I’m going to be a little more explosive, and that’s going to help,” Kazmir said. “It wasn’t a huge red flag, but I felt addressing it would really benefit me.”

With a stronger core and base, Scioscia believes Kazmir will put less strain on his arm.

“He’ll be in the right arm slot more often instead of dropping down to compensate or flying open,” Scioscia said. “It’s all connected. With a more consistent delivery, he’ll minimize risk to his arm, because it’s not doing more work than it has to.”

Case closed

Catcher Jeff Mathis, fresh off his arbitration victory over the Angels in a 3½-hour hearing in Tampa on Thursday, joined the team for workouts on Saturday sporting a 2010 salary of $1.3 million instead of the $700,000 the team filed at.

“It was one of the most interesting things I’ve ever been a part of,” Mathis said of the arbitration process. “The emotions, the ups and downs . . . You know what to expect because people tell you. But it was pretty detailed.”

Mathis hit only .211 with five home runs and 28 runs batted in last season, but he built his case around his superb defense and his .583 average and five doubles in the ALCS.

The Angels argued that catcher was worth significantly less, but there were no hard feelings.

“You know what’s going to happen,” Mathis said. “You just put your hard hat on and get through it.”

Alumni news

Former Angels Tim Salmon, Bobby Grich, Troy Percival, Mark Langston and Chuck Finley are scheduled to serve as guest instructors this spring.

It will mark Percival’s first such stint with the Angels since the spring of 2007, when the former closer, who had retired in 2006, laid the foundation for a comeback that resulted in him pitching parts of three more seasons with St. Louis and Tampa Bay.

“He started throwing and said, ‘Man, I feel pretty good,’ ” Scioscia said. “He went back home and was coaching [Little League]. Six months later, he was pitching for the Cardinals.”

mike.digiovanna@

latimes.com