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PITTSBURGH -- The Pittsburgh Pirates placed rookie pitcher Jared Jones on the 15-day injured list on Thursday with a right lat strain.

The Pirates made the move less than 24 hours after Jones left following five innings and 78 pitches in what became a 5-4 victory over the Cardinals.

Manager Derek Shelton downplayed the nature of the injury on Wednesday. He struck a more cautious tone on Thursday after a 3-2 loss to St. Louis, saying the team is still determining the severity of the injury.

"I think everyone knows what he means to us and where we're at, so, out of precaution he's still being evaluated," Shelton said.

Jones reported feeling discomfort in his right side during the game but said afterward, "it's nothing to be concerned about, I don't think."

Jones, 22, is 5-6 with a 3.56 ERA and 98 strikeouts in 91 innings. The Pirates have been carefully monitoring Jones' workload of late. The team skipped his return in the rotation last week in hopes of giving him a breather.

While Jones allowed just one run in five innings against St. Louis, he didn't hit 100 mph once, a rarity during his 16 starts.

The IL move means Jones won't be back until after the All-Star break.

Pittsburgh promoted outfielder Josh Palacios from Triple-A Indianapolis to take Jones' spot on the roster. Palacios hit .311 with five doubles and a home run in 21 games in the minors this season. Palacios walked as a pinch hitter on Thursday.