Matheny sat Carpenter on Thursday -- having previously earmarked the day as a good chance to find Carpenter some rest -- and then informed the third baseman he would not be traveling.
Carpenter had started each of the first 27 games this season. Now, he'll miss four straight. The Cardinals are hopeful he'll rejoin the team in Cleveland on Tuesday.
"I don't think it's coincidence that [this happens while] we're right in the middle of a 20-game stretch," Matheny said. "I don't think it's a coincidence that the intensity of the types of games we've been playing or a coincidence [that this is a] guy who just does not back off. It's full throttle all the time. We love how he goes about the game, but obviously there is a price to pay. It's a hard pace to keep up. He's been pushing and pushing and pushing just like a lot of these guys."
Carpenter has long been labeled the gym rat of this team, habitually showing up seven hours before game time and putting in some of the longest days during Spring Training. It was that work ethic, he has said, that allowed him to surge from a 13th-round Draft pick to two-time All-Star.
This health scare, however, will lead the Cardinals to suggest some changes.
"He is still relatively a young player, even though he's one of our veteran players," Matheny said. "But still redefining your program, redefining your routine just by listening to how your body responds. … I think, yeah, we're going to have to be real attentive to how he's grinding, and as a manager, being able to talk to him about this might be a day to take off."
Carpenter's absence leaves the Cardinals without their two-hole hitter for a key series against the Pirates. He had a walk-off sacrifice fly against Pittsburgh last weekend and hit a game-tying homer against Chicago on Tuesday. Carpenter ranks first in the Majors with 16 multi-hit games, 14 doubles and 20 extra-base hits heading into play Friday.
The club is also saddled with a three-man bench. Matheny has been playing one position player short for two weeks in order to stock his bullpen with an extra arm. He left open the possibility that the Cardinals might summon another position player this weekend if the bullpen is able to reset with a deep performance from a starter.
"It'll be another night of being creative as the game goes," Matheny said, "and realizing we don't have a lot here."
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, follow her on Twitter @LangoschMLB and like her Facebook page Jenifer Langosch for Cardinals.com. This story was not subject to the approval of Major League Baseball or its clubs.