PHILADELPHIA -- D-backs manager Bob Melvin expressed optimism on Saturday that right fielder Justin Upton would be ready to return to action when the All-Star break ends.

Upton, Arizona's 20-year-old right fielder, has not played since straining his left oblique muscle on his final swing during batting practice Wednesday in Washington. Upton was subsequently scratched from that night's lineup.

"Once we get these next three days off, we get him to a workout on Thursday, he should be a full go and hopefully starting the next day," Melvin said.

In the meantime, there is a chance Upton could be used as a pinch-runner in an emergency situation Saturday or Sunday against the Phillies, Melvin said.

Upton, selected by the D-backs as the first overall pick in the 2006 First-Year Player Draft, is hitting .242 with 11 home runs in his first full season in the Majors.

Alex Romero made his third consecutive start in right field Saturday. Romero had three hits in nine at-bats Thursday and Friday, including two doubles.

"He deserves a chance," Melvin said of Romero. "He's a guy that's very well prepared."