If the St. Louis Cardinals are going to keep pace or overtake the Chicago Cubs in the National League Central anytime soon, they're going to have to do it without ace Jack Flaherty. The Cardinals placed Flaherty on the injured list on Monday evening because of a "significant" oblique injury. 

"It's not a minimal situation," manager Mike Shildt told reporters, including Derrick Goold of the St. Louis Post-Dispatch. "It's a real strain, tear, I don't know which grade [they] want to call it. It's significant that Jack is going to miss some time. And it's going to be a while. We're still in the exploratory stage to determine how long."

In a corresponding move, the Cardinals promoted right-hander Johan Oviedo to the majors.

Flaherty, 25, had been brilliant in 11 starts this season. He'd averaged nearly six innings per outing while accumulating a 2.90 ERA (129 ERA+) and a 3.35 strikeout-to-walk ratio. Flaherty had also recorded a quality start in seven of those 11 attempts.

This isn't the first major injury sustained by the Cardinals rotation. Dakota Hudson will miss the season after undergoing Tommy John surgery last September, while Miles Mikolas rejoined the rotation for a start before returning to the injured list with forearm tightness.

With those three unavailable for the time being, the Cardinals have turned to a makeshift rotation that includes John Gant and now, possibly, Oviedo. In five appearances, four of them starts, Oviedo has posted a 5.40 ERA (70 ERA+) and a 1.07 strikeout-to-walk ratio. The Cardinals do have other options to take Flaherty's spot in the rotation: prospects Matthew Liberatore and Zack Thompson are both stationed in Triple-A (though neither's performance indicates that they're ready for an extended look in the Show).

The Cardinals entered Wednesday with a 31-24 record on the season, good for second place in the division. They trail the Cubs by a half game, though the two sides are scheduled to meet again for a three-game set in Chicago beginning on June 11.