ST. LOUIS -- The Padres' fading playoff hopes took another serious hit on Monday when right-hander Yu Darvish landed on the 15-day injured list with right elbow inflammation.

Darvish underwent further tests to determine the extent of the injury, and the team had not yet announced those results by Monday night. But Darvish, speaking after the Padres’ 4-1 victory over the Cardinals at Busch Stadium, characterized the injury as “discomfort” and indicated that he expects to return this year.

“I’m not thinking I’m done for the year,” Darvish said through interpreter Shingo Horie. “My intention is to come back and pitch again this season.”

Nonetheless, a 15-day IL stint -- backdated to Darvish's start on Friday against Milwaukee -- represents a sizable chunk of San Diego’s remaining season. The Padres have only 30 games left, during which they will need to overcome a seven-game deficit in the National League Wild Card race.

“I feel bad obviously,” Darvish said. “My responsibility here is to pitch for the team and to contribute to the team’s winning. So it is disappointing.”

Now the Padres must find a way back into the playoff picture with their rotation -- their biggest strength all season -- beginning to show cracks. Darvish joins Joe Musgrove on the IL after Musgrove landed there earlier this month with inflammation in his right shoulder capsule.

Over the weekend, Musgrove resumed playing catch. But he still has several hurdles left to clear before a return to the mound, and he won’t begin ramping up his throwing progression for another week or two. If the Padres can’t work their way back into the playoff picture, it’s likely the team will simply shut Musgrove down for the remainder of the season.

It's too early to say whether Darvish might be on the same trajectory. But the Padres signed both Darvish and Musgrove to long-term extensions in the past 13 months, and it stands to reason that they’d be cautious with the long-term health of both.

Then again, if the Padres work their way back into Wild Card contention, they’d like to have the option of calling upon a healthy Musgrove and/or Darvish down the stretch. For now, they’ll proceed with that as their plan.

The unspoken part of that plan: However improbable a Padres playoff run is, it’s even more unlikely with Darvish and Musgrove unavailable.

In 24 starts this season, Darvish has posted a 4.56 ERA. He’s shown flashes of his usual excellence, but on the whole, the 36-year-old veteran has turned in his most inconsistent season with San Diego.

On Monday, Darvish acknowledged that he’d been pitching through discomfort for “a couple months,” though it hadn’t previously reached this level. But he was removed after just 76 pitches on Friday, and over the weekend, his post-start soreness didn’t subside the way it usually does.

That led to Monday’s decision to place Darvish on the IL, with the full extent of the injury not yet known. At the very least, Darvish won’t be back until mid-September.

“When he's on [the IL] for 15 days, he's going to miss at least two starts,” Padres manager Bob Melvin said. “So, not really sure where it's going to go until we get a lot of information. He's been a guy that's pitched with stuff before, and he's been able to take the ball, at least in my tenure here, every single time. It's late in the year. He's pitched a lot. [We’re] just trying to be a little cautious with him, I think.”

Rich Hill, who had been removed from the rotation after some early struggles upon his arrival in San Diego, will slot into Darvish’s spot. He is set to start Wednesday’s series finale in St. Louis.