It's simply what he's brought to the diamond since he was a kid.
Either way, it's got everyone in the A's clubhouse wanting more of it. After all, it's what ultimately guided a 9-4 series-clinching victory over the Angels on Sunday.
Rosales, making his first start of the season, tallied a home run and a career-high four RBIs, and starter Dallas Braden hung around just long enough to tally a win and watch his club notch its fifth victory in seven days.
Rosales' homer came in the second off Angels starter Joe Saunders, who delivered a 1-0 fastball that ended up in the left-field seats. And Rosales, like he's done since Little League, rounded the bases in a speedy trot.
"I've done that ever since I could hit a home run," said Rosales, who also runs at full speed when walked. "It's the little kid in me."
It's also what jump started an A's comeback after Braden found himself down, 2-0, after the first. The southpaw then retired 13 in a row before allowing a run in the sixth, but Rosales put him in winning position for the first time all day courtesy of a go-ahead single in the seventh that brought home Kevin Kouzmanoff and Mark Ellis -- the latter also tallied an RBI on a ground-rule double in the frame.
"That just speaks to the kind of resiliency we're going to try to bring to the table every day," Braden said. "We're going to persevere. We're going to play our brand of baseball. We've seen it pay off thus far, and it's always encouraging coming out of the game and watching your team put some up quickly out there."
The A's combined to score five more runs in the final two frames to walk away with a valiant team effort in tow, and Rosales' name bounced around the A's clubhouse as energetically as his style of play afterward.
"He's somebody who probably needs to take a nap," Braden joked. "I feel like the guy plays like he hasn't slept in four days. I relish players like that because he doesn't know any other speed. Literally, it's to the wall with him.
"I think any team at any point in their season at any time of the day can feed off a guy like that, no matter what the scoreboard says. You get someone with that kind of energy and passion to play for your side, that gets you excited. You want to pitch in front of a guy like that. You want to root for a guy like that."
A laboring six innings gave Braden a line that had three runs, five hits, a walk and a pair of strikeouts attached to his name. He received support of one or zero runs in 10 of his 22 starts last season, so the fact that his team didn't start adding to the scoreboard until after he left didn't surprise him one bit.
"There might be a correlation there," he quipped. "Maybe I just need to not pitch, right?"
Braden admitted he struggled throughout the game before getting into what he deemed a "proverbial groove," but manager Bob Geren was impressed with the less obvious aspect of his pitcher's performance.
"He did a real nice job getting back into the game," Geren said. "It seemed like [the two runs] didn't bother him. Looking back to a few years ago, that would have rattled him a little bit, and he would have started throwing faster and harder, but he didn't panic. He actually slowed down and battled through."
Meanwhile, Saunders kept the A's in check through the first six frames, the only Oakland run coming on Rosales' solo shot before Saunders, too, retired 13 consecutive batters. But a pesky A's offense forced him out quickly in the seventh and an even peskier Oakland bullpen, led by rookie Tyson Ross, put the game away for good.
Ross, who made his Major League debut last week, recorded his first career save after tossing three innings of one-run ball while adding his name to a rather bountiful list of A's contributors in Sunday's rubber match.
Near the top of said list, perhaps even above Rosales, stood the unassuming Daric Barton, Braden argued. The A's first baseman laid down two sacrifice bunts in the game and also made more than one defensive highlight.
One of his more impressive catches came in the sixth when Kendry Morales popped up into foul territory, where Barton leaned over the A's dugout railing to record the out.
"Ridiculous," Braden said. "He kind of stole my thunder there on that one. I was probably going to make an even better play, but he did fine."
"I didn't want him to get hurt," Barton said in response.
Barton and the A's will carry their 5-2 record into Seattle, where they begin a three-game set against the Mariners on Monday. Oakland notched a 3-1 series victory over Seattle last week, and Braden is no believer in a fluke.
"Obviously the West is up for grabs, if you will," Braden said. "We don't feel that way. We feel like we're a front runner, and we feel we can compete with anybody. If we can continue to do what we've done so far, which is win the series, we'll be OK. It's a great way to start the month and obviously a great way to start the season."
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.