The Vikings host the San Diego Chargers on Friday night in the third game of the preseason, and there's a lot on the line.

With a cut-down date looming on Monday, it's crucial for many players to make their mark in this game or start preparing for employment elsewhere.

“For the guys who are on the bubble -- for the 75- as well as the 53-man roster -- when they get their turn, it's so important they show that they deserve to be a part of the next week's team," ," coach Leslie Frazier said.

The starters have something to show as well, and they'll get more than half the game to tune up for the regular season. Expect them to come out flying.

Here are a few storylines to watch:

Wide receiver play: After six targets and no catches last week, Devin Aromashodu has to produce or else give the impression that last week’s performance was the rule rather than the exception. Aromashodu, Stephen Burton and Michael Jenkins will all be auditioning for the starting spot left available by Jerome Simpson’s three-game suspension.

Run defense: Which run defense was the real deal? Was is the disaster of Week 1 (260 yards given up to the 49ers) or a bounce-back game in Week 2 (68 yards rushing yielded to the Bills)? The beefed up personnel (DE Jared Allen and DT Kevin Williams) in Week 2 certainly made a difference, but the defense must sustain it in a game when the emphasis will be on the run with Chargers QB Philip Rivers and TE Antonio Gates not suiting up. LB Jasper Brinkley needs a big game to convince the coaches that he should be the man in the middle.

Ponder proficiency: In five drives this season, QB Christian Ponder has put the team in scoring position every time. (No punts.) The offensive line has given him time to make good decisions. It has all added up to very little hand-wringing among the Viking faithful about their young quarterback. The first-team offense will get plenty of time against a decent defense to show what they can do and prove there are reasons for optimism in 2012.

Secondary switches: CB Chris Cook won’t be playing, so rookie CB Josh Robinson will platoon with veteran Chris Carr at one cornerback spot. Last week, Mistral Raymond and Harrison Smith started at the safety position and played a whole half, but Frazier said they would take another look at S Jamarca Sanford.  The test of the secondary may not be as great without Rivers and Gates in the game, but there will be plenty to watch nonetheless.

For more Vikings news and notes, follow Joe Oberle on Twitter @CBSSportsNFLMIN.