Cundiff, cut by the Washington Redskins in October after missing 5-of-12 field goal attempts, was signed on Tuesday and will compete with incumbent David Akers, who has also struggled making field goals.
Akers has hit on 29-of-42 attempts this season and gotten it through the uprights just 7-of-13 times from 40-49 yards, missing two chances from that range in Sunday's victory against Arizona.
Niners (11-4-1) coach Jim Harbaugh has given his players Monday, Tuesday and Wednesday off before beginning preparations for one of three possible opponents in their Jan 12 playoff game in San Francisco - Green Bay, Seattle or Washington.
"I'd like them to rest their minds, rest their bodies," Harbaugh said.
The Niners have a win over the Packers and split two games with the Seahawks this season but have yet to face the Redskins.
"I think we need to prepare equally," the coach said before conceding that Washington would require more advance work. "They're the ones we haven't seen yet. We have to run more computer data on them that we already have on some of the other teams.
"We'll get prepared for all the teams across the board."
