Angels acquire pitcher Tommy Hanson from Braves for Jordan Walden

The Angels added some much-needed rotation depth Friday, acquiring right-hander Tommy Hanson from the Atlanta Braves for reliever Jordan Walden, a trade General Manager Jerry Dipoto believes will “help both teams.”

How much it helps the Angels will hinge on how well Hanson, 26, rebounds from a subpar 2012 in which his earned-run average (4.48) went up and the average velocity of his fastball (89.7 mph) went down for a third straight season.

“I was more worried about staying healthy and felt a little tired down the stretch after the All-Star break,” said Hanson, who was slowed by a rotator-cuff tear and a back injury in 2011. “I didn’t feel I was as strong as I needed to be. But everything feels really good right now.”

The 6-foot-6, 220-pound Hanson, who pitched at Redlands East Valley High and Riverside City College, has a 45-32 career record and 3.61 ERA in four big league seasons. He went 13-10 with 161 strikeouts and 71 walks in 1742/3 innings in 2012.

Hanson finished third in 2009 National League rookie-of-the-year voting and looked strong in the first half of 2011, going 10-4 with a 2.44 ERA and holding opponents to a .190 average in 17 starts. But in 36 starts since, Hanson is 14-13 with a 4.96 ERA and .277 opponents’ average.

“It might not rate with past seasons, but our reports represent what we’ve always known about him, that he has two above-average breaking balls and misses bats,” Dipoto said. “He’s a year removed from anything involving his arm, and he had some back spasms a year ago. We feel it’s a good risk on a pitcher we believe in.”

Hanson’s ERA rose from 3.33 in 2010 to 3.60 in 2011 and 4.48 in 2012. His average fastball velocity in those years dropped from 92.7 to 91.2 to 89.7 mph.

“Tommy’s velocity was down a little bit, but he wasn’t hurt,” Atlanta GM Frank Wren told Braves reporters. “I think he started transitioning to a different kind of pitcher. He was trying to pitch with a little less velocity and use his off-speed stuff more.”

Hanson, who joins a rotation that currently includes Jered Weaver, C.J. Wilson, Garrett Richards and Jerome Williams, is entering his first year of arbitration and is projected to make $4 million. He’ll be under club control for three years.

Walden, a 24-year-old right-hander with a 97-mph fastball, was the Angels’ closer in 2011, going 5-5 with a 2.98 ERA and 32 saves. But he was slowed by a shoulder injury last season and relegated to middle relief, going 3-2 with a 3.46 ERA, and Wednesday’s signing of closer Ryan Madson made him expendable.

Also Friday, the team tendered contracts to its four arbitration-eligible players, Williams, reliever Kevin Jepsen, first baseman Kendrys Morales and third baseman Alberto Callaspo.

The Angels claimed outfielder Scott Cousins off waivers from Seattle and put him on the 40-man roster, which stands at 37 players.

mike.digiovanna@latimes.com