"It's a delicate balance," said Farrell. "That's why having guys who have been in that role prior is extremely valuable. Both Jonny and Mike have been in that somewhat and yet, tonight with Mike being in there, it's a matter of not letting him get too far away from his most recent activity and maybe Daniel's swing at times can get a little bit long and that's not to be critical. That's just monitoring the situation as it stands."
Getting playing time for Carp, who is hitting .317 with eight homers and 28 RBIs in 139 at-bats, has been an ongoing challenge for Farrell. Nava has 324 at-bats and was one of Boston's best hitters during the first half of 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.