The lefty-swinging Dunn has long been viewed by the A's as "a guy that fit our offensive mind" for his homers and walks, said assistant general manager David Forst. Dunn will join the A's in Oakland on Monday for the start of a six-game homestand against the Mariners and Astros, and he will primarily DH against right-handers, as John Jaso did before hitting the 7-day concussion DL.
The 34-year-old Dunn is in the final season of a four-year, $56 million deal and batting .220 with 20 homers, 54 RBIs and a .340 on-base percentage.
"Look, we're trying to do whatever we can to get some offense going here," said manager Bob Melvin, who had Dunn briefly in Arizona in 2008. "The guy has a history of hitting homers and getting on base. I know he's excited about being with us."
"I'm going to a place with a chance to not only get into the postseason but also have a legitimate chance to get a ring," Dunn told White Sox reporters Sunday. "Those chances don't come too often, so I'm very appreciative of the way it was handled and for [general manager] Rick [Hahn] and them to give me an opportunity to do it."
The A's spent July bolstering their rotation, first landing Jeff Samardzija and Jason Hammel before pulling off a stunner of a trade that brought them Jon Lester. But in getting one of the game's best pitchers, they had to part with one of the game's most feared hitters in Yoenis Cespedes.
The A's are 12-16 since the trade, and Cespedes' absence has magnified the club's recent offensive woes, which continued Saturday in a third consecutive loss to the first-place Angels. They've been shut out in two consecutive games and four times this month, entering Sunday with a 22-inning scoreless streak.
But the downfall began even before Cespedes departed, which is why the front office does not care to make any correlations between the trade and the club's recent play. The A's went 51-30 through the halfway point of the schedule (June 29) but are 27-27 since then, moving from a 5 1/2-game division lead to a four-game deficit.
"Going back to right before the All-Star break, we have not been the same offensive team we were the first three months of the year," said Forst. "Not to say we can't get back to doing that, because there are still a lot of guys in this lineup that have the ability to get on base and drive in runs.
"We're pitching great. We need to support those guys. This is basically the same group that has played well and scored runs before. I don't think this is going to last a whole other month."
Dunn brings 460 career home runs to Oakland, which ranks third most among active players.
"Obviously we've been struggling here offensively for the better part of the month," said Brandon Moss, batting .178 in August. "Dunn has the ability to change the game with one swing, something we haven't done a lot of.
"There are plenty of guys who are .220, .240 hitters that aren't in the lineup to go 2-for-3. They're in the lineup to get on base and drive in runs and hit the ball out of the ballpark, which is what he does."
Dunn welcomes the challenge of helping turn around an anemic A's offense.
"That's a lot of pressure that I want," he said. "It feels literally like Opening Day is tomorrow and it's going to be a completely new start for me."
The move, which had to be approved by Dunn because of his no-trade clause, is just as significant for him as it is for the A's. In 14 seasons, Dunn has yet to experience the playoffs, and his 1,976 games are the most by any active player without a postseason appearance.
The next-highest total is Alex Rios' 1,581 games played, followed by Brian Roberts (1,418), Nick Markakis (1,344) and Edwin Encarnacion (1,180).
"I think that's what's probably really exciting for him at this point, to come in and play meaningful games in September," said Melvin, "and help the team hopefully get to the postseason."
Sanburn, who was the A's second-round Draft pick in 2012, was 3-1 with six saves and a 3.28 ERA in 42 relief appearances for Class A Stockton this season.