Victorino, who has been dealing with left hamstring weakness for a large portion of the season, started in right field and batted second. Daniel Nava, originally slated to bat second and play right field, batted sixth and played left. Mike Carp, who was going to start in right field, instead started at first.
Napoli, who has slumped mightily in recent weeks, got a day off.
"It's something [Napoli has] been dealing with for quite some time and aggravated it last night on that double," Farrell said. "So when he came in today, [we] just felt like he needs a day down, at a minimum. It's in that plantar fasciitis area of the front foot."
While it would be easy to draw the conclusion of a correlation between Napoli's foot ailment and his slump, Farrell isn't sure there is one.
"No, I can't say that it's caused his swing to be less aggressive or it's caused him to not hit from a more powerful base," Farrell said. "Like I said, it's something he's been dealing with, but he has not expressed that as being a reason to why some of the streaks he's experienced."
As for Victorino, a day off on Saturday was viewed more as a luxury than a necessity.
"We're just kind of keeping the pulse of how guys are feeling physically and just building in a day when needed. Sometimes that's not afforded," Farrell said.
How much is the hamstring bothering the switch-hitting Victorino?
"Enough for him to hit from the right side of the plate against right-handed pitching as well," Farrell said. "It's more, again, trying to create the power base that we talked about from a hitter's standpoint. As far as his range in the outfield or ability to run the bases, that hasn't shown in those areas."
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.