Head athletic trainer Lonnie Soloff said Friday that an MRI showed a "high-grade left hamstring tear," and Dellucci would undergo surgery Thursday at the Cleveland Clinic.
"The good news is that this is not career-ending or even career-threatening," he said. "He will be back to 100 percent by the end of the season."
Eight weeks is the estimated amount of time for Dellucci to rehabilitate his hamstring and return to the lineup, although that could change. In the meantime, the Indians will continue to give different players a look at the position.
"We're going to let this play out, and see what direction it takes us in," manager Eric Wedge said. "We'll play whoever gives us the best chance to win."
Wedge added that he wouldn't be opposed to a permanent replacement, if a player were to emerge and overtake the others for the spot. One candidate would be Jason Michaels, who recorded five hits in 10 at-bats during the series with Philadelphia.
He's also a veteran player, having spent the last six years on a Major League roster. Wedge said that Michaels was one possibility, but he wasn't committing to anybody just yet.
If all goes as planned, Dellucci will make his return in mid-August, in time for the final weeks of the season. The hamstring that he tore was one of his two interior ones, which bodes well for long-term recovery. It is the one commonly taken out during ACL surgery to help reconstruct the ACL.
"In terms of long-term prognosis, it looks very good," Soloff said.
Dellucci's injury occurred in the fourth inning of Tuesday night's game while he was running to first base. Even after the injury, he tried to beat out the throw to first, making it safely by diving toward the base.
More injury news: Pitching prospect Adam Miller threw a simulated game for Triple-A Buffalo on Friday, throwing 34 pitches over two innings. He'll be evaluated on Saturday, and is expected to be cleared to pitch in Monday's game in Buffalo.
Miller strained a tendon in the middle finger of his right hand in early May, and has been recovering ever since. After Friday's simulated start, he told The Buffalo News that he felt fine.
"The finger is fine. I'm not even really thinking about it anymore," he said. "I'm just thinking like it's Spring Training, trying to get back into shape and get ready for games."
Here's the question: When was the last time the Indians played in Washington, D.C.?
Two Indians prospects were chosen to participate. Pitcher Chuck Lofgren, a lefty throwing for Double-A Akron, will pitch for the U.S. team, and catcher Max Ramirez, who plays for Class A Kingston, will catch for the World team.
Tribe tidbits: Indians players and coaches took in the sights of Washington on Friday as they visited the White House and Capitol buildings. Wedge said that it was a short visit, but he was impressed with the history and architecture of both buildings. ... Cleveland pitcher Fausto Carmona is still looking for the first hit of his Major League career. He had a sacrifice bunt against the Florida Marlins on June 12. ... A long week could get longer in Washington. Detroit and Cleveland are currently ranked one and two in runs scored, and the Tigers scored 32 runs during their three games against the Nationals
And the answer is: The Indians lost, 3-2, to the Washington Senators on Sept. 22, 1971. Only 1,458 fans were at RFK Stadium for that game.
On this date: In 1946, Bill Veeck became owner of the Cleveland Indians. Veeck was a pioneer in several aspects of the game, but not all of them continue to this day. In Cleveland, he had a movable fence installed that could be adjusted depending on the day's opponent and how strong its batters were. Veeck sold the Indians in 1949.
On deck: Cleveland stays in the nation's capital for the second of a three-game series against the Nationals. Right-hander Paul Byrd (6-3, 4.81 ERA) will pitch for the Indians and left-hander Matt Chico (3-5, 5.35 ERA) will go for the Nationals. Game time is 7:05 p.m. ET at RFK Stadium.
Michael Phillips is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.