"Erin should be fine," Frazier said. "… Soreness, so we decided to hold him back.
"Full go, unless he tells us it's bothering him, but at this point he'll be full go."
Henderson said he lobbied to practice on Friday but lost out in that discussion. However, he acknowledged he was initially concerned right after the injury occurred.
"It was on fire. It was a good bit of fire down there, but once it calmed down a little bit I realized it wasn't too bad, it wasn't too serious," Henderson said. "It was a little bit of a relief. It was a little nerve-wracking at first."
Henderson kicked a cooler full of cold towels and ice after the injury initially happened, but he said he held back on his kick when he saw what the cooler contained.
"I think he got the best of me. The cooler might have won that battle," he said. "I looked down just in time and saw it was wet towels so I assumed it was kind of full so I kind of back up on my kick."
While Henderson is expected to be a "full go" Sunday night, WR Jarius Wright (concussion) won't travel with the team to San Francisco. Wright passed all of his post-concussion tests, but the Vikings prefer to be cautious with his recovery.
That will open up more opportunities for rookie Cordarrelle Patterson to get some time with the first-team offense.
"He'll get a number of opportunities. That was planned anyways," Fraizer said of Patterson.
"He's done very well when it comes to learning our offense. I think last week, he had zero mental errors, so that was great. So that was very encouraging for all of us. He's done very well at adapting and adjusting to our offense. We haven't had to put together just a Cordarrelle package."
The first-team offense and defense are expected to play the entire first half and at least one series in the second half, but that doesn't apply to Adrian Peterson, who will see his first preseason action in two years Sunday night.
"We got some things in place for him, and we'll see how it goes as the game goes on. But he's had a great training camp for us. He's worked extremely hard. We'll see how it goes as the game goes," Frazier said.
Frazier, responding to a playful question, said Peterson isn't in the mix to play quarterback, but added: "That Adrian, now, he's a pretty good athlete. There aren't too many things he can't do. He's always talking to me about blocking a field goal or returning kickoffs: ‘Coach, I can be a great punt returner. Let me come off the edge. What tackle is going to block me coming off the edge?' There aren't many things he can't do on the football field."
Tim Yotter is the publisher of Viking Update. Follow Viking Update on Twitter and discuss this topic on our message boards. To become a subscriber to the Viking Update web site or magazine, click here.