There is no timetable for Sizemore's return, and with fellow outfielder Shin-Soo Choo still out another month with a broken left thumb, manager Manny Acta said the need for his team to make a trade to bolster the club is "an understatement."
The Indians expect to have a more detailed plan for Sizemore's recovery by the time they return home Thursday, but they're on top of the AL Central and could use some help to stay there.
"How can you substitute the absence of Choo and Grady Sizemore?" Acta said before the Indians played the Minnesota Twins. "I don't think that's a secret. We know that from top to bottom and we're working on it.
"People need to understand too that it takes two to tango. You can have all the Christmas lists and wishes, but you need to have somebody that you can engage with that's also going to work, at least for both sides," he said.
Sizemore was injured while running the bases against the Baltimore Orioles and was placed on the disabled list on Monday. He is hitting .237 with 10 homers and 29 RBIs in 61 games this season.
"It doesn't appear to be anything as serious as we might fear," Acta said of the injury.
Still, the surprising Indians began the day with a one-game lead over the Detroit Tigers in the division. They swept a doubleheader against the Twins on Monday.
One thing Acta made clear is the team is building for the long haul and won't sacrifice that plan for a short-term fix. Prized young players like infielder Lonnie Chisenhall won't be surrendered by general manager Chris Antonetti to bring in an established veteran.
"It's not because of a lack of diligence or trying. He's in conversation with a number of teams," Acta said. "But it's going to have to be something that makes sense for us. And we have made it clear that we're not going to mortgage our future."