Prado had an RBI double and is 10 for 15 this spring.
Carlos Quentin homered in his first at-bat of spring training, connecting on a 3-0 pitch from Arizona starter Randall Delgado in the second inning. Quentin had not appeared in a game since injuring his right knee in July and welcomed the live action.
"You take batting practice over and over, you need games to gauge where you're at," he said. "It was nice to get out there and see the ball out of the pitcher's hand. I was able to see it well and fortunately be successful in the first at-bat to get a hit out of the way."
As for swinging away on a 3-0 pitch, Quentin said he had the go-ahead from manager Bud Black, but he might not have done the same thing in the regular season.
"To be honest, I'm never comfortable doing it," Quentin said. "Spring training is the time to work on things and in some cases Buddy wants you to swing on that pitch. It was a good swing and I got a hold of one."
Diamondbacks: Delgado gave up two home runs in his second outing of the spring. He worked a 1-2-3 first inning, but allowed four earned runs on five hits and a walk while striking out two in 3 2/3 innings. The right-hander could win a spot at the back of Arizona's rotation or pitch out of the bullpen.
"He threw the ball really good for us as a starter last year," manager Kirk Gibson said. "We've seen him come out of the bullpen as a guy with some length. He also could be a seventh-inning guy. ... We like what we see with Randall."
Padres: Eric Stults was hit hard in his second outing this spring, which lasted only one inning. Stults threw 43 pitches, allowing three earned runs on two doubles, a single and two walks. He struck out one.
"There are things I do want to work on," he said. "The main thing is getting a feel for pitches and finding a good tempo with my delivery. I feel like that's been a little bit off this spring."
Diamondbacks: Bronson Arroyo was scratched from his scheduled start because of a stiff back. Gibson said Arroyo did not throw Tuesday, but the manager wasn't concerned that Arroyo would miss a considerable amount of time. The veteran right-hander signed a two-year contract with Arizona in February.
"We've got a long ways to go," Gibson said. "He's never really had a history of missing starts so I feel confident he'll be fine."
Journeyman Matt Tuiasosopo's shot at making Arizona's 25-man roster might have improved when he drilled a bases-loaded, one-out single in the first inning that scored two runs.
Gibson said the 27-year-old's experience playing multiple positions is a plus. Tuiasosopo can play both corner outfield spots, third base and first base.
"He definitely could be a guy who comes into play for us with his versatility, which I like," Gibson said.