SAN FRANCISCO -- Right-hander Chris Paddack was placed on the 10-day injured list with right elbow inflammation on Monday, the latest blow in a brutal second half's worth of injury luck for the Padres.

Just when the San Diego rotation seemed to be getting healthy, left-hander Blake Snell exited his start on Sunday with left adductor tightness. Now Paddack finds himself on the IL, with his status in question moving forward.

Paddack first felt tightness after his start on Saturday against the Dodgers. He was feeling better on Monday and played catch at 75 feet, but the feeling hadn't quite fully dissipated. That's when the Padres opted to place Paddack on the IL -- meaning he will miss his scheduled start on Thursday at the very least.

"He still felt a little something in there," said Padres manager Jayce Tingler. "The best thing, we thought, is to get him the nine or 10 days off and see where we're at and see if he can make a start when we get back for that San Francisco series [next week]."

Paddack would be eligible to return for the second game of that series on Sept. 22. But he'll need to clear a few hurdles with his elbow, the first of which would be playing catch without feeling any tightness. The Padres have reason to be extra cautious with Paddack, who underwent Tommy John surgery in 2016 and has only recently begun to routinely throw a curveball.

In the meantime, the Padres are in need of a starter for Thursday's series finale against the Giants -- a crucial series as they look to hang on to their tenuous lead in the National League Wild Card race. It's possible they go with a bullpen day or move left-hander Ryan Weathers back into the rotation.

Then again, there's also the looming question of Snell's scheduled start on Friday. Tingler reported that Snell woke up feeling sore and that he’d be getting treatment all week, but his start on Friday is very much up in the air.

"We'll see with continued treatment and where that goes," Tingler said. "It's too early to say right now. We're still shooting for the start in St. Louis. But it's too early to say if that's a real possibility or not. We just don't know yet."

If the situation turns dire enough that the Padres are without two of their five starters, that would seemingly raise the possibility of a callup for top pitching prospect MacKenzie Gore. It's been a rough season for Gore, who spent two months working through some mechanical issues at the team’s complex in Arizona.

Gore is currently with Double-A San Antonio and pitched five innings of two-run ball on Saturday. The Padres had no plans for a September callup for Gore, hoping to get him a few successful starts in the Minors that he could build on, going into the offseason. But they also didn’t plan for two of their five starters to go down in the span of two days.

However the Padres replace Paddack -- and potentially Snell, too -- this much is clear: These questions are becoming all too familiar. Paddack, who owns a 5.07 ERA in 23 outings this season, recently missed a month with a left oblique strain. Right-hander Yu Darvish has also spent multiple stints on the IL in the second half with back and hip tightness.

The Padres' rotation depth has been seriously tested in the second half, and thus far they haven't had many answers. They’ll need to come up with a few by Thursday.