Valdez learned he was headed to Miami about 11 a.m. PT on Friday, and he traveled cross country and was ready for batting practice Saturday.
With a young pitching staff, the Marlins are trying to put as solid a defense together as they can.
"Obviously, we'd love to have a guy who can really hit, too," manager Mike Redmond said. "But at the same time, having our pitching staff as young as it is, we're going to have to play defense. We're going to have to get every out. That's probably going to be the No. 1 thing.
"We're probably going to play a lot of close games. Every mistake that we make could be costly. We definitely have got to secure the ball and get every out that we can."
The Marlins are in the process of finalizing their roster, and they are weighing their utility infield options.
"I want to show them that I can play, and hopefully they give me a chance," Valdez said.
Valdez joins the mix with Nick Green, Chris Valaika and Matt Downs.
The Marlins open April 1 at the Nationals, and the team is hoping to have the roster pretty much set by the middle of next week.
This will be Valdez's second stint in the Marlins' organization. As a prospect in 2004, he was traded to the White Sox for reliever Billy Koch.
Valdez has spent parts of seven seasons in the big leagues. From 2010-11, he was with the Phillies, and a year ago he appeared in 77 games with the Reds.
With the Phillies, Valdez was a teammate of current Marlins Placido Polanco and Greg Dobbs.
"It feels familiar," Valdez said of being back in Marlins' camp.
In 439 big league games, Valdez is a career .236 hitter.
The Marlins are seeking as much depth as possible in the infield. Currently, second baseman Donovan Solano is resting a sore back. Polanco missed time this spring with a strained right oblique.
"I'm looking for an opportunity," Valdez said. "I am trying to do the best I can, and let them make their decision."