Casey

BOSTON — When the Red Sox signed first baseman Sean Casey in February, the team explained to the 11-year veteran that it was looking for him to take a reserve role.

He would be serving as a backup to Golden Glover Kevin Youkilis, the Sox said.

Unless, that is, someone went down with an injury.

So there Casey was Wednesday night, sitting in the dugout at Fenway watching his new team play Detroit — one of his former teams — when Sox manager Terry Francona came up to him and said: “You’re in there.”

Third baseman Mike Lowell had reinjured his left thumb while making a diving backhanded stop of an Ivan Rodriguez grounder at third base in the first inning. Although he finished the inning and even went out on the field for the second, Lowell came out of the game before it was Boston’s turn at the plate.

Casey — who played first, while Youkilis moved over to third — responded well to the last-minute assignment, going 2-for-4 with a single and a double.

“He said, ‘You’re in there,’ ” said Casey, who hit a line drive to center and eventually scored in his first at-bat. “And I was like, ‘Where is Lowell hitting? Fifth?’ They said, ‘You’re up after Manny [Ramirez].’ . . . Oh wow, it all happened so fast. It was good to get a hit right off the bat. It kind of settles you in a little bit.”

Starting at first base and batting eighth last night, Casey made some significant contributions to Boston’s 12-6 win over the Tigers. He went 2-for-5, hitting a ground-rule double down the right-field line in his first at-bat, contributing an RBI on a groundout to first in Boston’s four-run fourth, and lining a two-run single to right in the seventh.

“I think you could tell Case in December to go hit and he could probably put a good swing on it,” Francona said. “He’s a good hitter. And I told him the first week of the year that that’s how this happens. You sit for a week and don’t play, and all of a sudden you’re in there and this is why we got him. It’s hard to find guys that can sit the bench and that are good enough hitters to go in and play and get hits. And I think we think he’s one of them. And he has the attitude to match that and handle it. So I think we’re pretty fortunate.”

“It’ll be good to be out there and it’ll also be good to have Mike back. That’s the Catch-22,” said Casey.

cthorn@projo.com