SANTA CLARA -- Frank Gore is opening eyes with how well he's run in 33 carries this season. Guess who else has impressed with 33 carries? A guy who tore the anterior cruciate ligament in his left knee on Christmas Eve.
That would be former NFL rushing champion Adrian Peterson of the Minnesota Vikings, who host the 49ers face Sunday.
"He felt so much better this week in comparison to after the first game," Vikings coach Leslie Frazier said in a Wednesday morning conference call with Bay Area reporters. "We feel he's really making progress on a physical standpoint. He's playing well.
"The concern is how is his body responding to the contact we couldn't give him in training camp. So far, so good."
Peterson has run for 144 yards (4.4 per carry) and two touchdowns. He ranked 18th among the NFL's top rushers last season with 970 yards, with 12 touchdown runs.
Such high production is nothing new for the backbone of the Vikings offense. Peterson ran for 1,298 in 2010 (sixth in league); 1,383 yards in 2009 (fifth); 1,760 in 2008 (first); and 1,341 in 2007 (second) en route to AP Offensive Rookie of the Year honors.
Frazier said Peterson and Stanford product Toby Gerhart have been rotating series and that a healthy Peterson could see more action against the 49ers' challenging defense Sunday.
Such a game plan seemed inconceivable last Christmas.
"When that injury occurred, you hear the word 'ACL' and you're thinking a year
"To sit here and tell you I expected him to make it back and play as well as he did in the first game, I'd be lying. It was amazing. It still is."
Gore, who overcame tore the ACL in both of his knees in college, is not surprised by Peterson's remarkable comeback.
"Not really, because you see a guy play and you know that he's a hard worker," Gore said. "And they have so much new technology that will get you back there fast. Once you've got work ethic, you should be fine. So it doesn't surprise me at all."
Gore ranks fourth in the league with 201 yards rushing for a 6.1 yards-per-carry average, and he's scored a touchdown in each of the 49ers' opening wins. His 23-yard touchdown run at Green Bay is his longest of the season. Did you know: Gore and the Titan's Chris Johnson lead active rushers with 28 career runs over 30 yards?
Gore's next carry will push him past Roger Craig for the most in 49ers history (1,687 attempts).
"It's a big deal, but it doesn't really matter," Gore said. "I'm happy God gave me an opportunity to play the game I love to play. With everything I've been through, I give my all on the practice field and in games."