It was Nava's third start of the season, with the first two at designated hitter.
Why did Nava get Sunday's start instead of Mike Carp, the team's other backup first baseman?
"The way he played in Spring Training. The way he's adapted, the way he's swung the bat. All things considered, that's why he's at first base," said Farrell. "I think he's made the transition and incorporated first base defensively pretty seamlessly."
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.