LONDON – The language of the NFL is ugly and blunt as the business end of a rusty hammer. Players chop, block, cut, penetrate, stick, jam, explode. They throw bombs and sustain stingers. Their language is evocative and brutal.

The most dramatic word Vikings fullback Jerome Felton uses is "puncture,'' a vivid description in which he stars as the can opener, the defense becomes thin aluminum and Adrian Peterson bursts through the fresh opening like well-shaken seltzer.

"I just know how Adrian wants to run the football, and that's to be fast,'' Felton said. "So my goal is to hit the hole and try to puncture it and not try to stop up the hole.''

The word is precise. As Peterson's favorite lead blocker, Felton doesn't need to flatten three defenders. He merely needs to temporarily create a small opening for a very fast back. Puncture is the perfect word, and Peterson is eager to hear it used in a few sentences in a postgame locker room.

Last year, Peterson averaged an astonishing 6.9 yards per carry when he ran behind Felton, and 4.6 yards per carry behind other fullbacks and in formations without a fullback, according to ESPN Stats&Information. This year, through three games without Felton, Peterson is averaging 4.1 yards per carry.

After rushing for 2,097 yards last season, Peterson said Felton should receive credit for "six or seven hundred'' of them. That's also precise.

Jerome Felton (42) punched a hole for Adrian Peterson (28). “I think I allow him to run with confidence,” Felton said.

In Peterson's first four full seasons, he averaged 1,445 yards. Last year, he challenged Eric Dickerson's single-season rushing record despite facing defenses that massed bodies at the line of scrimmage like they were filming a "World War Z" prequel.

With Felton punching holes where there should have been none, Peterson actually took advantage of the packed lines, finding himself with open space once he passed the line of scrimmage. Felton's blocking and Peterson's praise led to him being named to the Pro Bowl.

"I feel like I made a difference,'' Felton said. "We had a lot of success last year. I'm looking forward to getting that done this year.''

The NFL suspended Felton for the first three games of this season in connection with a drunken-driving arrest in May 2012. He underwent an emergency appendectomy on Aug. 14.

He has watched the first three games with a sense of alarm. Since Peterson broke his first carry of the season for a 78-yard touchdown, he has averaged just under 3 yards a carry.

"It's been a really long few weeks,'' Felton said. "I felt like I left some people high and dry, and that's never a good feeling. It's been really long. But the team has done a really good job of keeping me upbeat and keeping me working so I would be ready when the time came.

"I've been sitting alone in my apartment during these games, yelling at the television, feeling frustrated, aggravated. I'm glad it's over.''

The most dramatic news of the week came at the NFL's most important position. Matt Cassel will replace the injured and ineffective Christian Ponder.

Statistically, there isn't much difference between Cassel and Ponder. Felton's return could mean more to Peterson and the offense than even a quarterback change.

"I have to bring a physical presence,'' Felton said. "We're a physical team. Adrian knows what I'm all about. I think I allow him to run with confidence. When he can do that, he's pretty amazing.''

Felton discussed the subtle techniques he employs, using his hands to trap and turn a defender, using his feet to position himself for a strike.

"It's kind of a tough deal,'' Felton said. "It's a train wreck on every play. I think 80 percent of it is mentality and 20 percent is technique. You have to have the right mentality, and then technique separates the good ones from the great ones.''