McDonald was activated off the disabled list this week and entered Friday's game as a pinch runner when Crawford injured his hamstring while running down the first-base line. He enters Saturday's game hitting .138 in 29 at-bats this season.
With left-hander Randy Wolf pitching for the Brewers, Mike Cameron will be inserted into the lineup for the Sox. He is batting ninth and playing right field in place of J.D. Drew.
Wolf is 2-1 with a 2.73 ERA in five career starts against the Sox. The 34-year-old is 4-4 with a 3.20 ERA for the Brew Crew this season.
Another lefty, Jon Lester, will get the nod for the Sox. He'll be seeking a major-league leading 10th win of the season.
In his last start, Lester pitched eight innings of one-run ball in a 14-1 win over the Blue Jays at Rogers Centre.
Here is a look at each team's lineup for Saturday's game.
Boston Red Sox
Jacoby Ellsbury, CF
Dustin Pedroia, 2B
Kevin Youkilis, 3B
Adrian Gonzalez, 1B
David Ortiz, DH
Darnell McDonald, LF
Marco Scutaro, SS
Jarrod Saltalamacchia, C
Mike Cameron, RF
Milwaukee Brewers
Rickie Weeks, DH
Corey Hart, RF
Ryan Braun, LF
Prince Fielder, 1B
Casey McGehee, 3B
Yuniesky Betancourt, SS
Josh Wilson, 2B
Carlos Gomez, CF
George Kottaras, C
