"Can he start [Friday] ? No," Bochy said. "But it's a five-game series. If we think he can help coming off the bench, maybe start the back end of this series, then we probably would activate him."
Nunez is batting .288 with 40 stolen bases this season, including .269 with 13 steals in 50 games since the Giants acquired him July 28.
Nunez's unavailability raises another question for the Giants: Who replaces him?
Conor Gillaspie hit safely in his final five regular-season games while filling in for Nunez, who was injured Sept. 25 at San Diego. Gillaspie proceeded to deliver Wednesday night's decisive three-run homer in the Giants' Wild Card Game triumph at New York.
But Bochy has preferred to platoon the left-handed-batting Gillaspie with right-handed-batting Kelby Tomlinson. If Bochy were to stick to that plan, Gillaspie would be benched in Friday's Division Series opener against Cubs lefty Jon Lester.
Bochy also has a choice to make in center field between left-handed-batting Denard Span and right-handed-swinging Gorkys Hernandez.
Bochy didn't reveal his lineup plans, noting that he wants to discuss his decision with the involved players before he releases the news to reporters.
Rotation not finalized
Bochy emphasized that he has not settled on his starting rotation for the series beyond Johnny Cueto, who received Friday's Game 1 assignment.
If Bochy simply were to keep his top four starters in order, Matt Moore would start Saturday's Game 2, followed by Jeff Samardzija in Monday's Game 3 at San Francisco's AT&T Park.
However, Madison Bumgarner -- he of the 1.94 career postseason ERA -- will have had his usual four days' rest by Monday. It would be difficult to fathom Bochy passing up a chance to start Bumgarner at AT&T Park, where he's 48-30 with a 2.74 ERA lifetime. That includes a 9-4 record with a 2.14 ERA this season.
Chris Haft has covered the Giants since 2005, and for MLB.com since 2007. Follow him on Twitter at @sfgiantsbeat and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.