DENVER -- Good thing the Padres fortified their rotation depth at the Trade Deadline. They’re going to need it.

A day after San Diego landed Rich Hill in a trade with Pittsburgh, ace right-hander Joe Musgrove was scratched from Wednesday’s start against the Rockies with right shoulder soreness. Right-hander Nick Martinez got the ball in his place in what manager Bob Melvin said would be “a full bullpen day.”

The team called Musgrove’s shoulder issue “minor,” and Melvin noted that he’s hopeful Musgrove would be able to make his next start on turn next Tuesday in Seattle. But that will obviously be contingent on how Musgrove feels in the coming days.

 “He’s been experiencing a little bit of shoulder stiffness in his last couple of starts,” Melvin said. “He’s been pitching through it but at this point in time, we just don’t want it to get any worse, so we’ll probably end up skipping him a start. I think we’re looking at the first game of the Seattle series. It’s just something we want to get ahead of.”

Even for one start, the Padres can ill afford to be without Musgrove, who has a 3.05 ERA across 17 outings this season. The 30-year-old right-hander dealt with some injury trouble early in the season, including a fractured big toe during Spring Training. But he’s been mostly dominant over the past two months, posting a 2.25 ERA in June and a 1.45 mark in July.

Musgrove now joins right-hander Michael Wacha as Padres pitchers working their way back from shoulder injuries. Wacha has missed the past month with shoulder inflammation but is expected to return to the rotation in mid-August. He threw two simulated innings on Monday at Petco Park and could make a rehab start in the near future.

As for Hill, his arrival gives the Padres an option this weekend in a key four-game series against the Dodgers. Hill is expected to join the team in San Diego on Friday when that series opens, and it seems likely he’ll make his Padres debut on Sunday Night Baseball, when the team has a rotation vacancy.

The Padres acquired Hill, despite already boasting a five-man rotation that has been excellent this season. Their depth beyond those five was thin, and the entirety of that five-man rotation is 30 or older. They simply couldn’t assume the injury risk.

Beginning in mid-August, the Padres have a critical stretch with 26 games in 27 days, mostly against postseason contenders. Ideally, Wacha and Musgrove will be back by then, leaving the Padres to decide whether to use a six-man rotation. That’s a question they would love to answer eventually, if it means all six of their starters are healthy.