"Looking at the schedule, the late-night travel, [Friday's] situation, so we've got to -- with all of our players -- just rotate guys through," Farrell said.
Ortiz had been in the starting lineup for the club's first four games. He has been dealing with a tight right calf muscle since Spring Training. But, that is not the primary reason for the off-day, according to Farrell.
"I think he deals with a little bit of tightness from time to time, but as much as anything, this was more of a planned down day," Farrell said.
Through the first four games, Ortiz was batting .353 (6-for-17) with a home run and three RBIs. He went 1-for-4 with a strikeout in Friday's home opener -- a 6-2 loss to the Brewers. He entered Saturday night's 7-6 loss to the Brewers as a pinch-hitter in the ninth and grounded out.
In the original lineup, Mike Napoli was the designated hitter, batting fourth, with Mike Carp playing first base and batting fifth. However, Carp was scratched with lower back tightness, moving Daniel Nava from left field to first and giving Jonny Gomes the start in left. Nava hit third, with Gomes in the No. 6 slot. Just before the game, Will Middlebrooks was removed from the lineup. Jonathan Herrera got the start at third and batted eighth. Middlebrooks is scheduled to undergo an MRI on Sunday morning for a right calf strain.
Grady Sizemore led off for the Red Sox. It's a slot he's familiar with -- 3,319 of his 4,059 career plate appearances have been in the No. 1 spot. In his first three games with the Red Sox, though, he hit in the six-hole. Sizemore is a career .274 hitter, with a .366 on-base and .488 slugging percentage batting leadoff, but hasn't hit at the top of the lineup since Sept. 8, 2011, while with the Indians.
Sizemore entered Saturday hitting .300 (3-for-10) with a home run and two walks. In the loss to Milwaukee, he went 0-for-4 with a walk and scored a run.
"He's obviously gotten on base here with some regularity in a spot where he's been familiar with his entire career," Farrell said. "He'll just give us a little bit of a spark at the top of the lineup.
"Just the way he's responding to games played, the aggressiveness in which he's running the bases, the frequency he's getting on base, all the above puts him in the spot tonight."
Sizemore had been out of baseball since Sept. 22, 2011, because of injuries. The Sox have said they would monitor him this season. On Friday, Farrell suggested Sizemore would play Saturday and possibly get Sunday off. Farrell is not concerned about the possibility of an extra at-bat on Saturday.
"We'll continue to monitor how he comes out of each and every game, and see where the best spot is for he and for our lineup," Farrell said.
Maureen Mullen is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.