Sizemore went 0-for-4 in a series-opening 4-1 loss; Nava contributed a diving catch and his first homer of the season.
"It's as much about trying to get Daniel going," said Farrell. "We still value the on-base, which Daniel has a strong track record of that, and yet right now we feel like we've got to give him an opportunity to get his feet on the ground offensively. Once he does, we feel like he'll be in that spot. We're just trying to make the most of the current streaks or the way guys are swinging the bat right now."
As for the outfield, Nava, who is typically Farrell's first option in left, played right field. Jackie Bradley Jr., who has been spending a lot of time in right of late, started in center.
The reason for those switches? Yankee Stadium.
"The ground that's going to be covered here in Yankee Stadium is almost the reverse of what we deal with at Fenway," said Farrell. "We'll keep Jackie in center field and get Grady over in left for that particular reason -- to cover the vast space that's on the left side of the field."
Sizemore was typically unfazed by both his movement in the batting order and the outfield.
"I play anywhere and I'll hit anywhere," said Sizemore. "It's not an issue for me."
The Red Sox did have Sizemore spend some time in left field during Spring Training.