Bill Musgrave is a barrel of laughs. That barrel, apparently, is buried beneath a missile silo at an undisclosed location.

The Vikings offensive coordinator is one of those coaches who holds a high-profile job in which he may determine the joy-meter reading for an entire state with his decision-making but publicly displays the excitement level of a social anxiety test subject. He’s a brilliant conversationalist if you like cautious body language.

His calm will be tested Sunday. He’ll coach Christian Ponder in an important game on the road against a quality defense in a stadium where the Vikings have averaged 11 points in their past three visits.

This week, before he began invoking his right to remain uninteresting, Musgrave offered a somewhat straight answer to a straight question. When his quarterback plays poorly, is Musgrave more likely to alter the offense to create more comfort for the quarterback, or to push the quarterback to properly run the offense?

“An easy answer would be to say it’s a combination of both,’’ Musgrave said. “We have a young guy that has made a bunch of good plays in the short time that he’s been here. He’s also had his mistakes. So we’re of the mind-set of continuing to push him.

“We’re on the demanding side, and I know he’s on the demanding side of himself, too, so we want to keep pushing and working for development.’’

That’s the right approach. Ponder was so awful last week that it would be tempting to scale back the play-calling this week to emphasize what he does best, and what is safest. Bootlegs to the right. Wide receiver screens. Long passes that allow the receiver to adjust to the ball, as Jerome Simpson did, brilliantly, twice last week.

That approach might give the Vikings an improved chance of winning but would encourage defenses to pay even more attention to Adrian Peterson and would limit the influence of Greg Jennings and Cordarrelle Patterson, who should be two of the Vikings’ most important players.

And if Ponder executed a simplified game plan and it actually worked, the Vikings could find themselves investing another year in a quarterback based on his ability to hand off and avoid throwing interceptions, instead of an ability to run a modern NFL offense.

According to ESPN Stats & Info, last week the Vikings faced the NFL’s highest percentage of eight-man defensive fronts (36). Ponder compiled a quarterback rating of 0.4 in those situations. The rest of the NFL’s quarterbacks, when faced with eight-man fronts, threw five touchdown passes, zero interceptions and compiled a 51.1 rating.

Ponder and his backup, Matt Cassel, have both built a significant body of work as NFL starters. Both have paled in comparison to the league’s established stars (Tom Brady, Peyton Manning, Drew Brees, Aaron Rodgers) and new wave (Colin Kaepernick, Russell Wilson, Robert Griffin, Andrew Luck). The difference between the two was supposed to be Ponder’s ability to avoid turnovers.

If Ponder is going to commit turnovers, as he did last week, he loses his advantage over Cassel. Cassel’s career completion percentage is .589. He has thrown 82 touchdowns and 57 interceptions. His career quarterback rating is 80.4. Ponder’s numbers, while working with the advantage of Adrian Peterson in his backfield, are: .594 completion percentage, 32 touchdowns, 28 interceptions, 76.4 rating.

This could be one of the most important days of Ponder’s career. If he performs efficiently and the Vikings win, his coaches will be praised for their patience. If, like last week, even his completions are off target, his only advantage over Cassel will be that the Vikings used a first-round pick on him.

Offensive coordinators always receive blame when an offense fails, and Musgrave is culpable for allowing Patterson on the field for only five plays last week, but he designed an offense that offered Ponder open receivers all over the field.

Musgrave is right. Ponder should be challenged to operate a full-fledged offense. In his third season in the NFL, a league where young quarterbacks are thriving, there should be no training wheels. It’s time to put up or sit down.