By looking at the three quarterbacks during practice Monday you could see how the Vikings are heading into the final preseason game. Starter Donovan McNabb was wearing a baseball cap, not a helmet, and he wasn't practicing. He was loose, relaxed.

But, for a while after the practice ended, Christian Ponder and Joe Webb kept working. On one field, Webb did extra sprints back and forth. On the other field, with offensive coordinator Bill Musgrave watching, Ponder worked on throwing down-and-out routes.

This is the final audition to be McNabb's understudy.

McNabb won't play Thursday against Houston. Ponder, the team's first-round draft pick in April, will start. Ponder and Webb, who is in his second season, will split the snaps over the course of four quarters.

Hence the extra work. This is an important game for both of them.

"We definitely want to see both guys, Christian along with Joe, create some separation for that No. 2 spot," Vikings coach Leslie Frazier said. "Maybe this game will be an indication of which guy should be No. 2."

No pressure guys, it's only your immediate future at stake here. As the team's top draft pick, with a sparkling résumé from a big-time school, Ponder clearly is being groomed as the eventual starter.

But, in the short term, the job of No. 2 on opening day still is up for grabs. Both Ponder and Webb have had their moments, but both have looked better on the run than when in the pocket.

Webb, with a season under his belt, has the edge in NFL experience, a gap that Ponder, without the aid of minicamps, has worked to close.

Both will get a lot of reps Thursday.

"It will be my best chance to get my rhythm, throw some more balls, get a lot more snaps," Ponder said. "It will be good for me."

Said Webb: "I think we've been doing a good job of competing against one another throughout the whole camp. Just going to the last game, you want to continue to get better."

Webb was the first QB off the bench in the first and third preseason games. Ponder had that role in the second preseason game.

Neither has seen a lot of extended playing time, so Thursday should be illuminating.

In three preseason games Ponder has completed 17 of 33 passes for 207 yards with no TDs or interceptions and a passer rating of 71.1.

Webb has completed 12 of 23 passes for 170 yards with no TDs, one interception and a rushing touchdown for a rating of 58.2.

Both have, at times, appeared to struggle going through progressions while in the pocket, and each has looked more comfortable leaving the pocket and throwing on the run.

Saturday, Webb led an 81-yard third-quarter TD drive, completing passes of 23 and 43 yards before scoring on a 10-yard scramble.

Ponder struggled in his first possession, then led a two-minute drill that died at the Dallas 16 when tight end Allen Reisner was unable to get out of bounds after a catch as time ran out.

Musgrave has shown flexibility when calling plays. According to Ponder, Musgrave allows his QBs to rank their favorite plays in each game situation, then tries to accommodate those choices.

"Two days before the game, we get a game plan of what we're going to run," Ponder said. "And we basically get to choose our top two plays from each section. ... And that's what we're going to run when we get in there. It's great when we have input."

With input comes expectations, of course. Webb and Ponder both know they have a lot of improving to do.

"I feel I've definitely learned a lot," Ponder said. "I think I've progressed. Right now I'm in that thinking stage, that learning curve state right now. I'm adjusting.''

Said Webb, "There are always ways to get better."