GREEN BAY, WIS. - Christian Ponder removed his shirt late Saturday night, and the back of his right arm was a dark shade of purple.

"It's basically a deep thigh bruise but in my throwing arm," he said.

Publicly, the Vikings didn't act overly alarmed by Ponder's injury this week, but that large bruise ultimately prevented him from playing in his first playoff game.

Ponder's surprise scratch left Joe Webb as the Vikings' emergency starter against Green Bay, but any thought of Webb shining in the moment evaporated when he bounced his first pass off the Lambeau Field turf. That set the stage for a night of wild throws and general incompetence by Webb in a 24-10 loss that left an ugly stain on an otherwise successful Vikings season.

Technically, Ponder described his injury as a deep contusion on his triceps, though the Vikings said it was his elbow on the injury report. He said the injury limited his flexibility and prevented him from raising the ball to his chest for his normal throwing motion.

Ponder tested his arm in pregame by making 10 throws, none with any zip. He said those soft tosses were the extent of his velocity. "It was clear it wasn't going to work," Ponder said.

Ponder said he consulted with the team's coaches and medical staff and that they made a "cumulative" decision for him to be inactive. He said the pain was tolerable but that he lacked the velocity to be functional. "I think everyone kind of decided with how limited I was that it definitely was better for Joe to be out there," he said.

Ponder's injury managed to accomplish two things: He quieted those who still believe Webb is a better option, and he likely angered a healthy segment of fans by not playing through the injury.

That's always a tricky discussion because no one other than Ponder knows how his arm feels. We're not in his mind and body. Football players are conditioned -- and expected -- to play through injuries and maladies, especially in the postseason. It's part of their job description. We expect them to fight through it at all costs.

But if a quarterback can't throw the ball any harder than Ponder did in early warmups, he's doing more harm than good by being on the field.

Webb undoubtedly will be ridiculed for his ineffectiveness, but he's not an NFL-caliber quarterback and was put in a tough spot. He's elusive when a play breaks down and he's able to freelance, but he did not attempt a pass all season before Saturday, and he's just not an accurate passer.

The Vikings cut veteran Sage Rosenfels and didn't sign a competent backup to Ponder. That was shortsighted on their part, and it cost them at the worst possible time.

Ponder banged his throwing arm on the helmet of Packers safety Morgan Burnett last Sunday. He said his arm improved throughout the week and he felt optimistic that he would play. Leslie Frazier listed Ponder as questionable on the final injury report, but given the general lack of concern, that designation felt like a touch of gamesmanship and subterfuge on Frazier's part to keep the Packers guessing.

Ponder made some throws in practice the previous two days and threw once more in the hotel pool Saturday morning. "The arm just never got to a point where it was good enough to be out there," he said.

It's disappointing because Ponder played the best game of his career last week with a playoff berth at stake. He didn't just manage the game. He didn't just hand the ball to Adrian Peterson and get out of the way. He made clutch throws at critical times. He threw three touchdown passes and posted a career-high 120.2 passer rating.

The Vikings thought he would build on that performance. He acted loose and relaxed this week. He projected a sense of calm after showing that he could rise to the occasion in a big moment. Nothing seemed amiss.

By Saturday afternoon, that all changed. So did the Vikings' hopes of a playoff upset. "I took a lot to get here," Ponder said. "It was frustrating having to watch, but it was something out of my control."

Chip Scoggins • ascoggins@startribune.com