The Braves traded from an area of depth and shed some payroll -- Hanson will make about $4 million in his first year of arbitration, while Walden is still making close to the minimum -- in hopes of adding a leadoff-hitting outfielder.
The Angels, meanwhile, parted ways with a reliever who would at best be fifth on their depth chart and filled one of the two holes they had in their rotation. Hanson joins a staff that includes Jered Weaver and C.J. Wilson, with the young Garrett Richards also in the mix and Jerome Williams adding depth.
Acquiring the right-hander is not expected to affect the Angels' pursuit of Zack Greinke, a source said, but it does provide an important safety net three days before the start of the Winter Meetings.
"To be able to plug in a 26-year-old who remains with the club for the next three years, it's a good move for us," Dipoto said in a conference call. "Obviously, it gives us some guidance as we head into the Winter Meetings. We still have some spots to fill on our roster, but this allows us the ability to go in with a little better understanding on where we're operating from today."
Hanson has gone 45-32 with a 3.61 ERA in 108 starts while spending his entire four-year career with the Braves.
He wasn't taken until the 22nd round of the 2005 First-Year Player Draft, but Hanson was among baseball's best prospects by the time he reached the upper levels and quickly established himself as one of the Majors' top young arms. From 2009-11, a span that began with him finishing third in National League Rookie of the Year voting, Hanson averaged 11 wins and compiled a 3.28 ERA.
But he missed the last two months of the 2011 season because of lingering right shoulder pain, the result of a small tear in his rotator cuff, and struggled the following year.
Hanson made 31 starts and compiled 174 2/3 innings, but he was hit around in the second half, missed two weeks with back spasms and finished with a career-high 4.48 ERA and 1.15 WHIP. His velocity also continued to drop, from 92.7 mph in 2010 to 91.1 mph in 2011 to 89.6 mph in 2012, according to FanGraphs.com.
Now, Hanson said, "I feel great." He admitted to being "a little bit tired down the stretch" this past season, but believes he can counter that by tweaking his offseason program. Braves GM Frank Wren said Hanson "wasn't hurt" in 2012, adding that his velocity drop resulted from him "transitioning to a different kind of pitcher" by using his offspeed pitches more often.
"I don't think it would be fair to qualify it as a disappointing season," Dipoto said. "It may not stack up rate-wise with where he's been before, but his velocity remained consistent across the board, month to month, as last season went by. Our scouting reports on him represent what we've always known about Tommy, which is that he features two above-average breaking balls and as a general rule misses bats.
"He's a year-plus removed from anything involving his arm, and obviously he had some back spasms a year ago, but we feel like it's a good risk on a pitcher we really believe in."
Hanson, a Scott Boras client, moved from Tulsa, Okla., to Southern California when he was 2, attending Redlands East Valley High School and Riverside Community College. Yes, like Madson, he rooted for the Angels.
"Where I grew up, there's a ton of Angels fans," said Hanson, who was in Alabama to attend the wedding of Braves closer Craig Kimbrel when he heard the news. "I grew up going to Angels games, and I pitched there in 2011, and I was very excited to pitch there after going to so many games growing up. Immediately, I was shocked, and now I'm just very excited. And I wish Spring Training was tomorrow."
Who the Angels sign to finish rounding out the rotation before then is the big -- perhaps final -- question.
If Greinke's price tag gets up to $150 million, as is being reported, the Angels will have little choice but to turn elsewhere. And one very real option is to counter by signing a cheaper starter (they've been linked to Ryan Dempster) and another reliever (they've met with Japanese closer Kyuji Fujikawa).
There's certainly more room in the bullpen now that Walden is gone.
Walden, whose fastball has been clocked in the triple-digits, had a solid year as the Angels' closer in 2011, posting a 2.98 ERA while going 32-for-42 in saves. But the 2012 season was a step back.
Walden was replaced as closer in late April, missed six weeks on the disabled list with neck soreness and a right biceps strain, lost a tick or two off his fastball, struggled to gain command of secondary pitches and finished the season with a 3.46 ERA in 45 appearances.
With the Angels, he was behind Scott Downs, Kevin Jepsen, Ernesto Frieri and Madson in the pecking order. Now he'll join a lights-out bullpen that includes Kimbrel, Eric O'Flaherty and Jonny Venters.
"As I've talked about throughout the offseason, we're trying to develop as much depth as we can one through 12," Dipoto said. "And the addition of Ryan Madson, to join Ernesto Frieri and Kevin Jepsen and Scott Downs, we felt that this was a very logical way to create one-through-12 depth with a starter rather than a reliever."