They announced that Utley, who felt a burning sensation on his right side when taking swings during batting practice Monday in Miami, will be placed on the 15-day DL with what they've called a "very mild" Grade 1 strained oblique. They said there is no intercostal or rib-cage injury. He is eligible to be activated June 5.
The Phillies selected infielder Michael Martinez's contract from Triple-A Lehigh Valley to take Utley's place on the roster. Martinez has hit .188 with a .512 on-base-plus-slugging percentage in parts of two seasons with the Phillies. He hit .226 with a .570 OPS with Lehigh Valley this season.
Phillies general manager Ruben Amaro Jr. said the typical recovery for Utley's injury is two to four weeks.
"We do believe and hope that Chase will be ready to play in Philadelphia within 15 days," Amaro said in a statement.
Utley received an MRI exam Thursday. He expressed his concerns about the injury before Wednesday's 3-0 victory over the Marlins at Marlins Park.
"It definitely scared me a little bit," he said. "My first swing I took in BP, I felt something. My second swing, I felt it again. My third swing, I felt it again. After the fourth swing, I realized something wasn't right. You want to be careful with these things, because they could linger and get worse if you try to play through it. I think we caught it early enough, but it's hard to know until we have some imaging on it."
Utley has spoken with teammates and former teammates who have had similar injuries in the past. Several Phillies pitchers have spent time on the DL in recent seasons because of strained obliques, but so have position players like catcher Carlos Ruiz and former Phillies outfielder Jayson Werth. Ruiz spent 23 days on the DL in 2009, while Werth spent 15 days.
"The main thing they said was, 'Don't rush back,'" Utley said. "That's when you can make it worse and prolong the time you're out."
The Phillies certainly will miss Utley's bat. He's hitting .272 with seven doubles, two triples, seven home runs and 25 RBIs in 44 games. He has an .814 on-base-plus-slugging percentage.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.