Five things: What to watch for Saturday

NASHVILLE, TENN. -- The Vikings have numerous questions that need to be answered before the Sept. 11 regular-season opener at San Diego.

While it's likely going to take the entire preseason to get some of the answers, the Vikings' preseason opener on Saturday against the Tennessee Titans should at least help to begin providing clarity on some issues. Here are five things to keep an eye on as the Vikings and Titans play at 7 p.m.

1) Left tackle: The Vikings only plan to play their starters for a series or two but it will be interesting to see how new left tackle Charlie Johnson does against Titans right end Jason Jones, who has been moved from tackle. Johnson, signed as a free agent, is replacing Bryant McKinnie and looked completely overmatched at times in practice last week against Jared Allen.

Granted, Allen is an elite right end but it had to be a concern to the Vikings to see Johnson get beat so badly at times. The question is was Johnson just adjusting to a new system and trying to shake off the rust from the lockout or was he providing an example of why the Colts were planning to move him from tackle to guard if he stayed in Indianapolis?

The Vikings offensive line already had some question marks entering the season, but until McKinnie showed up at nearly 400 pounds and was released, left tackle wasn't thought to be one of the bigger concerns (pun might have been intended).

Donovan McNabb might have been mobile at one time, but he's now a 34-year-old quarterback who spends far more time trying to find receivers than Peyton Manning did when Johnson protected his blindside. If Johnson's struggles continue the Vikings might have to move to an Option B at left tackle. That could mean sliding Phil Loadholt from the right to the left side, although coach Leslie Frazier has said that is something he doesn't want to have to do.

If you're wondering, Pat Brown is listed as the Vikings backup left tackle and has been working with the second team.

Johnson missed time in training camp this week because of a hamstring injury, giving Sanford a chance to get more reps with the first team. That isn't going to hurt his case. It also doesn't hurt that Sanford is an aggressive safety and while that might cause him to make mistaks it also provides an intensity that has been lacking at times from the safeties on this team in recent seasons.

Johnson, a second-round pick in 2008, started 15 games in 2009 but lost his job to Husain Abdullah last year and saw action in only seven games (two starts). Sanford was a seventh-round selection in 2009 and has made three starts in his first two seasons.

One would think that Johnson and Sanford would split the starts in these first two games as coaches try to get a look at them playing against the top competition on the field.

3) Backup quarterback: Don't blink or you're going to miss McNabb's appearance. However, it could get a bit more interesting after that.

Not sure I buy that Joe Webb and Christian Ponder are really competing for the No. 2 job, but Frazier has been alternating the two between second- and third-team reps and there have been times that Webb definitely has looked to be sharper.

The one thing we do know is Rhett Bomar is going to see plenty of playing time in the second half and with McNabb, Webb and Ponder in front of him there is little chance Bomar is around for very long.

4) Wide open? One would think that Percy Harvin, Bernard Berrian and Michael Jenkins are assured of jobs on the 53-man roster. But after that there will be plenty of competition for the Nos. 4-5 jobs at wide receiver.

The candidates include Jaymar Johnson (who worked extremely hard this offseason and has looked good in camp); Manny Arceneaux; Devin Aromashodu; Greg Camarillo; and Juaquin Iglesias. That is leaving out Stephen Burton, Dominique Johnson and Andre Holmes but those three would have to have superior camps in order to make this team. Burton, for one, struggled much of last week.

If you asked me right now, I'd say Johnson, Aromashodu and Camarillo are the ones really fighting for the final two spots, assuming Frazier doesn't decide to keep six wide receivers. It will be interesting to see how much playing time offensive coordinator Bill Musgrave plans to try to get each of the wide receivers.

5) Bounce back for corner? Chris Cook had a terrific training camp last year after being selected in the second round by the Vikings, but things went downhill from there. Cook had arthroscopic surgeries on both knees after suffering meniscus tears, with the first coming in the preseason.

Ideally, the Viking would love to see Cook take his opportunity and win a job playing in the nickel defense. That would mean he would shift to left corner when Antoine Winfield goes inside to cover the slot. Cook has said he's healthy this summer and this will be his first chance to show that his level of play has risen to the form we saw a year ago at this time.