"It's going to require some time down," said manager John Farrell. "We'll have a better read on his potential availability probably seven to 10 days into the 15-day DL stint, and we'll see how he responds to treatment from that point."
The move was made retroactive to Sunday, a day after Victorino suffered the injury in Boston's final Grapefruit League game in Florida.
Victorino is first eligible to play on April 15, when the Red Sox open a three-game series in Chicago, but it's too early to say if he'll be ready by then.
"The overall projected date of return, it will be when he's ready to go," Farrell said. "Whether that's 15 days or beyond remains to be seen."
During Victorino's absence, Farrell will mix and match his lineup, opening up playing opportunities for Bradley, Carp and Jonny Gomes.
The Red Sox know that it is critical to try to keep Victorino healthy for the long haul, considering how important he is for the team.
"He's done such a great job for us, and you talk about a Gold Glove guy in right field, a top of the order hitter that, instinctually, is a very good player," Farrell said. "As we tapped into our depth last year many times over, unfortunately we're doing it on Day One, so Vic will be missed but we've got good players to step in and ready to contribute."
Victorino was expected to arrive in Baltimore by the Opening Day festivities, and will join the team for their trip to the White House on Tuesday.
The presence of Bradley will make it easier for Farrell to rest Sizemore, who last played in the Majors in 2011, early in the season.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.