Eduardo Nunez "tweaked" his left oblique muscle over the weekend but hoped to avoid the disabled list. When he tried to take batting practice on Tuesday, he knew he couldn't.

With Nunez unable to swing without soreness, the Twins placed the utility infielder on the 15-day DL after Tuesday's game, and replaced him with another infielder — veteran Doug Bernier, who has spent time in Minnesota at the end of the past two seasons. Bernier owns a .233 average in 40 career games with the Twins.

Bernier was added to the 40-man roster, filling the vacancy created when Ervin Santana was suspended last month, and will report in time for Wednesday's game. The 34-year-old Bernier is batting .250 at Class AAA Rochester.

The Twins chose Bernier, who more easily fills Nunez's role as a utility infielder, over such prospects as Josmil Pinto, who is hitting .324 in the minors, or Aaron Hicks, who is at .318.

Rosario tours outfield

Eddie Rosario took a tour of Target Field before batting practice on Tuesday afternoon, with coach Butch Davis as his guide. They walked under the overhang in right field, examined the fence that walls off the bullpen in center, got a close-up look at the flower pots in left field. "You just show him the [grass] surface, how to check the wind, what happens to balls that bounce off the padding, or the harder walls," Davis said. "It's sort of a chance to learn your surroundings."

When Terry Ryan informed him Monday that he's now a major leaguer, Rosario said, "It's a dream." He called his parents, Eddie Sr. and Maria, who quickly made arrangement to fly from San Juan, Puerto Rico, to Minneapolis.

He'll play left field here, once he gets into the lineup. Manager Paul Molitor decided to wait another day to allow Rosario to get better acquainted with Target Field, but the 23-year-old rookie will likely play on Wednesday.

"A lot of times when a guy comes up, you like to get him in there as quickly as you possibly can to get his feet wet," Molitor said. "I like the way the lineup looked last night, I like that [Eduardo] Escobar is beginning to get in a groove. So I decided to give Eddie a day."

Rosario said Tuesday's tour was helpful. "When the ball hits the wall, it's coming back hard," Rosario said he learned. "If the ball is going to hit the wall, you've got to come back three or four steps and wait for the ball to hit the wall."

Molitor is eager to see what Rosario can do at the plate, too. "He kind of has a quiet demeanor, but I think he really is a guy who likes to be in the game and at the dish when the game is on the line," Molitor said. "Some of the best at-bats I've seen him have in the minor leagues would be late in games, [and] you'd see the other team's top minor league prospect, who is a closer, come into the game and Eddie would find a way to get something done."

Since he was a kid

Molitor left a congratulatory voice mail Tuesday for new Brewers manager Craig Counsell.

"I've known Craig since he was a toddler," Molitor said, because Counsell's father, John, was the Brewers' community relations director while Molitor was a player in Milwaukee. "I'm glad he's getting an opportunity. I think he's going to be really good at it."

National exposure

• MLB Network has added a live broadcast of Thursday's 12:10 p.m. game against Oakland to its schedule, the Twins announced.