MIAMI -- Everything you need to know about the gene pool from which A's reliever Dan Otero comes can be gleaned from the fact that Dolores Otero just bought a new car.

Dolores Otero, Dan's grandmother, is 93.

"She wants to be able to get around," said Jorge Otero, Dan's father and Dolores' son. "She goes shopping. She goes to lunch. She goes to the gym."

One place Dolores Otero won't drive is Marlins Park, though it isn't far from the Miami area home she's lived in for half a century. She will go as a passenger as Otero's family descends in force this weekend on the home of the Miami Marlins with the A's making their first-ever visit to the 3-year-old stadium.

The kind of inner drive that gets Dolores Otero to the gym is common to the Oteros. Dolores' late husband, Alberto, was passionate about baseball in his native Cuba. Jorge and his two siblings -- brother Alberto Jr. and sister Nuria -- all went to Princeton as swimmers after helping Miami Springs High win the Florida state title.

So why isn't Otero, who at 6-feet-3, 215 pounds is built along the same lines as Michael Phelps (6-4, 195), an Olympic swimmer? Here's a hint: His nickname at home is "The Rock."

"He swam like a rock," Jorge Otero said. "He was never going to be a swimmer. Besides, he liked to do too many other sports."

Dan Otero particularly liked baseball. And golf, where he had close to a scratch game at one point. And tennis, where his mom, Patti, "always beat me, which I did not like," Dan Otero said. "It took me a long time to learn how to win."

As was the case for many Cuban citizens, Alberto and Dolores packed up their three kids in 1961 and moved to Florida, with the Castro regime taking hold. Alberto, who died in 2008, brought his love of baseball with him, and in Dan and his brother Ryan, now at the University of Miami, baseball took root.

"I think that my grandfather was happy that I chose baseball," Dan Otero said. "He wanted to have at least one baseball player in the family. It was his passion. He was the reason my dad was a baseball fan. They'd listen to Yankees games on the radio together."

And they'd put Dan in any baseball league they could find. Jorge did some coaching. Alberto, with his ever-present camcorder, got it all down on tapes that still have a special place in Dolores Otero's home.

"There are boxes of VCR tapes," Dan Otero said. "Sometimes at Christmas or whenever we all get together, they'll pull one out of me, or my brother or my sister (Christina) playing sports."

They were all good athletes. Christina, who just finished law school, was a collegiate rower. Ryan and Dan chose baseball.

The thing is, baseball didn't exactly choose him. He pitched for Duke rather than Princeton because "he wanted to be in the ACC," Jorge Otero said.

"I remember facing him in college," said fellow A's reliever Sean Doolittle, who pitched and played first base at Virginia. "It was always a tough time. He didn't throw as hard as some, but he could throw the sinker to both sides of the plate and a slider for a strike any time."

Otero's lack of velocity made him just a 21st-round draft pick. But if Otero's first two seasons with the A's have proven anything, he's the glue in a good Oakland bullpen, with a combined 8-1 record and 1.79 ERA.

"There's no role he's not suited for," manager Bob Melvin said. "When you need a ground ball, he's the guy."

That comes from grandpa.

"I remember one time in the first inning of a Little League game, I struck out the side and he was mad at me," Dan Otero said. "He said 'You can't pitch a complete game if you are striking out too many. Get ground balls. I remember that very clearly. And lo and behold, I try to get ground balls still."

This weekend, for the first time as a major-leaguer, he gets the chance to do it where he grew up.

"I'll enjoy the off-day, but come Friday, it will be just like another series," he said.

Then he reconsidered.

"There will be a decent-sized crowd there for the Otero cheering section," Otero said. "Hopefully they won't be too loud and obnoxious. But sometimes that Miami-ness comes out."

The Rock returns.

For more on the A's, see John Hickey's Insider at www.ibabuzz.com/athletics. Follow him on Twitter at twitter.com/JHickey3.