AP

JUPITER, Fla. (AP) — Matt Carpenter couldn't simply stand there and take it.

Under orders not to swing at any pitches for fear of aggravating his stiff lower back, the St. Louis Cardinals star did the next best thing — he bunted for a single.

"I saw the shift and it was either stand there and take a strike or try to get a base-hit bunt," he said Thursday. Carpenter said. "I saw that opportunity and did it."

In the lineup for defensive purposes only — he's now the full-time first baseman — Carpenter batted ninth against Houston. He'd missed Grapefruit League games for more than a week because of his back problem and had been forced him to withdraw from the World Baseball Classic.

When Carpenter came up, the Astros shifted shortstop Marwin Gonzalez to the second base side of the bag.

After taking a ball and a strike, Carpenter fouled off a bunt attempt, prompting the Astros to slide third baseman Colin Moran well off the line to the shortstop spot.

Carpenter then pushed a 1-2 offering past pitcher David Paulino and glided easily to first base, sheepishly looking back into the dugout as he crossed the bag.

"I wasn't going to swing and wasn't going to do anything, really," Carpenter said. "I was just going to take. An opportunity came about and I bunted."

Carpenter spent the past couple days hitting off a tee and expects to be cleared to take full swings in the batting cage by Monday. He figures he'll be ready to take unrestricted hacks in game by the beginning of next weekend.

"I don't feel the real need to rush it," he said.

Carpenter has primarily played second and third base during his major league career, though he did start 35 games at first base last season. A full-time move to first this season will let St. Louis to play either Jhonny Peralta or Jedd Gyorko at third, thereby strengthening their overall defense.

Prior to Thursday, he'd only played in three Grapefruit League games, totaling five at-bats.

"This is a new position for him on an everyday basis," St. Louis manager Mike Matheny said. "To get out there and have the game speed, it's really important."

The Cardinals are concerned that the stiff back could lead to the same oblique issue that landed Carpenter on the disabled list last season. The three-time All-Star led the league with 199 hits in 2013 but hit only .271 with 21 homers last year.

Swinging is currently the only activity that aggravates his back.

Carpenter appeared comfortable at first for five innings and had left the complex well before the final out was recorded in Houston's 3-0 victory. A second-inning throw by Gyorko from third that was high and to the right field side of the bag required Carpenter to shuffle his feet on the bag while making the catch. He also tracked down Teoscar Hernandez's foul ball in the bullpen down the right field line.

This is the second consecutive spring the Cardinals have sent one of their stars to the plate with orders not to swing.

Catcher Yadier Molina caught a couple games where he batted under the same restrictions last spring in an effort to build his stamina behind the plate as he worked his way back from thumb surgery.