David Ortiz’s move complicates things for Red Sox

ST. LOUIS — Pitching aside, Boston’s margin for error in the next three games of the World Series could be razor thin.

Because the Red Sox are one of the few teams that use one player — David Ortiz — exclusively as the designated hitter against American League teams, they could feel the loss of that position more than any AL team in recent history.

Ortiz will shift from DH to first base Saturday night for Game 3. Manager John Farrell had little choice but to sit Mike Napoli, who usually plays first base but is resigned to coming off the bench.

Thanks to Ortiz, Red Sox DHs led the AL with 33 home runs, 110 RBIs and a .310 batting average in 2013.

After a seven-for-35 start in the postseason, Ortiz is four for six with two home runs and five RBIs in the World Series. Napoli has played first base well, but Farrell is hesitant to use him at catcher, where he began his career with the Angels.

Napoli hasn’t caught a game this season because of a hip condition that prompted the Red Sox to restructure his contract from three years to a one-year offer loaded with incentives.

Both players present a threat at the plate but have struggled pinch-hitting. Napoli is a lifetime .105 hitter (four for 38) as a pinch hitter and was one for three this season in that role. Ortiz is batting .186 (16-for 87) with five home runs as a pinch-hitter over his career, and he went one for two with a home run in that role this season.

Ortiz started six games at first base this season, batting .158 (3-for-19) and not committing an error.

Meanwhile, if Clay Buchholz’s right shoulder prevents him from starting, left-hander Felix Doubront could take his spot on the mound Sunday in Game 4.

Small expectations

Cardinals first baseman Allen Craig returns to the field for the first time since suffering an ankle injury Sept. 4, and Manager Mike Matheny isn’t expecting a Gold Glove-caliber performance.

“Defensively, we’ll take whatever we can get,” Matheny said Friday at a news conference. “Every day is another step. [Saturday], we’ll get him to take more ground balls and get him moving. He also has the potential to possibly play in the outfield. So we’re giving him a little more work and exposure out there.”

Matheny said the Cardinals won’t rush Craig, who could return to his designated hitter duties if there is a Game 6 in Boston.

Short hops

Cardinals ace Adam Wainwright will remain on regular four days’ rest and start Game 5 on Monday night, with Lance Lynn starting Game 4. Had the Cardinals trailed 3-0 in the series, Wainwright would have moved up on short rest, Matheny said. . . . Cardinals right fielder Carlos Beltran didn’t seem to aggravate his bruised rib during Thursday’s game in which he collected two hits and drove in an insurance run. “He looked pretty normal to me,” Matheny said.

mgonzales@tribune.com