TEMPE, Ariz. -- Fear not, Angels fans. Mike Trout assures you he is not fat.

Yes, the 21-year-old outfielder reported to spring training at 241 pounds, about 10 to 15 pounds more than he weighed in 2012 and five pounds heavier than slugger Albert Pujols, who checked in at 236.

And, yes, with his thick neck and muscular build, the reigning American League rookie of the year looks more like an NFL fullback than a major league leadoff hitter, causing an uproar among fans on Twitter and message boards, where Trout has been called, among other things, “Blimpy” and the “Hindenburg.”

But most of the added weight is muscle — Trout’s body fat is 9% — and he expects to lose about 10 pounds during camp, which would put him right around the weight he finished last season at, 230 pounds.

And he has not gained 30 pounds, as some have speculated. Though he was listed at 6-foot-1 and 210 pounds last season, he actually weighed between 225 and 230.

“I think it’s pretty funny,” Trout said of the response to his weight gain. “I usually lose five to 10 pounds in spring. I figured if I came in at the weight I want to play at and lost five to 10 pounds, I’d be underweight to start the season.”

The concern of fans is understandable. Why mess with your body composition after a season in which you hit .326 with 30 home runs, 83 runs batted in, 129 runs and 49 stolen bases and placed second in most-valuable-player voting?

But Trout feels comfortable.

“Don’t worry about it, I’m fine,” he said. “This is nothing too crazy. I feel fast. I feel quick. I should be good.”

As good as he was in 2012? Trout’s biggest challenge may be living up to the expectations he created last season, when he quickly established himself as one of the best players in the game.

“He wasn’t caught up in numbers last year, and I don’t think he will be this year,” Manager Mike Scioscia said. “He’s so dynamic he can help the team in so many ways, from defense to baserunning, situational hitting and production in the batter’s box.

“He doesn’t have to put us on his shoulders. At times last year, he did, but Mike doesn’t have to be that player. He just has to find ways to help us win.”

Fully armed

Second baseman Howie Kendrick feels a big difference in his throwing arm after having surgery in October to remove calcium deposits in his elbow. He had stiffness and fluid buildup in his elbow over the last few years and needed a cortisone shot in 2012.

“My arm doesn’t lock up,” Kendrick said. “Last winter, it locked up on the second day I threw, and there were days when it was really stiff. Now, I feel good.”

Short hops

Reliever Ryan Madson, shut down for two weeks after developing soreness in his surgically repaired right elbow, is scheduled to resume throwing Monday. … Ernesto Frieri’s new pitch, which Scioscia identified as a changeup, is actually a cut fastball, which the reliever worked on all winter. But since camp started, Frieri has decided to add a changeup, as well. “We’ll see what happens in spring training,” Frieri said. “The pitching coach will determine whether it’s good enough to use in a game.”

mike.digiovanna@latimes.com