Safety Donte Whitner says the "small sprain" to his knee won't keep him out of the 49ers' game Sunday. But he also won't be 100 percent.

Whitner didn't have to risk re-injuring it on a muddy practice field Friday, at least. The 49ers moved their practice site from The Grove in the Hertfordshire countryside to Allianz Park, an artificial-turf field that's home to Saracens Rugby Club.

Whitner and the 49ers (5-2) are prepared, however, for encountering a potential slippery surface at Wembley Stadium, where they'll face the winless Jacksonville Jaguars (0-7).

"We'll deal with it and use longer cleats," Whitner said. "A lot of times on surfaces that are wet, you shorten your steps, try not to overstride and slip.

"In that situation, the offense has an advantage on us because they know their moves and their routes, and we have to react."

Whitner is all for the long-shot possibility of the NFL planting a team in London, although he said "a lot of guys" feel otherwise.

"I love London. This is my eighth time here," Whitner said. "I'd definitely be one of those to sign up for that team. It'd be cool. It's not that much different from playing all the way in San Francisco and having an East Coast game."