LONDON – There's a saying in baseball. When a pitcher falls apart, you don't need to look at the boxscore for proof. You need only listen to the sound of the bats.

Here is the Vikings' corollary: To judge a quarterback, you don't always need to calculate passer rating. You need only see the posture of the wide receivers.

Christian Ponder rarely threw the ball downfield with timing and authority. Even his completions left his wideouts leaning, leaping or diving, and his incompletions left them looking skyward, seeking patience.

Sunday in London, Matt Cassel threw passes that enabled Vikings wideouts to catch comfortably, run aggressively and celebrate often. That's the difference between him and Ponder, and the reason Vikings coach Leslie Frazier needs to keep him in the lineup no matter the state of Ponder's sore ribs.

Asked whether the Vikings had found their starter, Adrian Peterson grinned and said, "What do you think?''

Frazier was more evasive. He began his postgame news conference following the Vikings' 34-27 victory over Pittsburgh by noting that Cassel didn't turn the ball over. Later, he said, "Christian's our quarterback.'' Pressed, Frazier said he didn't want to make any "premature'' decisions.

Vikings players talked about their 34-27 victory against the Pittsburg Steelers in London.
Video (01:12): Players confident after 34-27 win

That's the right thing to do, Les: Watch film, hold meetings, consult advisers, study NFL history, and then name Cassel the starter.

Cassel completed 16 of 25 passes for 248 yards, two touchdowns and no interceptions. He fumbled once, and was lucky a teammate recovered. He threw one deep pass and one short pass that could have been intercepted. The difference between him and Ponder was not the quality of their poor throws; it was the quality of their quality throws.

Cassel threw the ball quickly and accurately enough that his wideouts caught passes with their defensive backs in vulnerable positions.

Before Sunday, Greg Jennings had caught 11 passes for 160 yards and no touchdowns. His longest reception was 27 yards. In the first quarter, Cassel hit Jennings with a quick 5-yard pass that enabled him to weave for a 70-yard touchdown. Jennings finished with three catches for 92 yards and two touchdowns.

Jerome Simpson entered the game with 12 catches for 218 yards. Cassel found him in single coverage often early in the game. Simpson caught seven passes for 124 yards, including a 51-yard catch-and-run.

Ponder favored tight ends and backs, because he's cautious. Cassel favored wide receivers. He threw 19 of his 25 passes toward wideouts.

After the game, receiver Jarius Wright again spoke of Cassel's command of the huddle. So did Peterson.

"He's more vocal,'' Peterson said. "He was out there saying his two cents worth in the huddle and you see guys buying into it, and keeping the huddle together and that's all you can ask for …

"He did a good job.''

Add those comments to those made by other Vikings this week, and you hear a team begging its coach to stick with Cassel.

They can see what even Londoners new to American football could see: Cassel makes quick decisions and throws. If a receiver runs a down-and-out, the ball is in the air before the receiver comes out of his break. Ponder too often waits for a receiver to get open, then eases the ball in his general direction.

It's time for the Vikings to stop playing nanny. They didn't sign a legitimate backup in Ponder's second year because they didn't want Ponder to feel pressure. They didn't consider benching Ponder during seasons or games because they didn't want to dampen his confidence or incite a controversy.

Sunday night, Frazier kept playing that game, pretending that he doesn't know who the better quarterback is for his team right now. "I don't want to just go by what I saw with the naked eye,'' he said.

Naked eyes are best for discovering the naked truth: Cassel is much closer to being a functional NFL starter right now than Ponder. The players know it. Despite his coyness, Frazier has got to know it, too.

Jim Souhan can be heard weekdays at noon and Sundays from 10 to noon on 1500 ESPN. His Twitter name is @SouhanStrib. • jsouhan@startribune.com