MANKATO -- Finally. Football returns to Mall of America Field on Friday. Vikings-Texans, 7 p.m.

Get excited. But understand the disclaimers. Vikings coach Leslie Frazier isn't concerned with the score.

"From a win-loss standpoint, there's not a lot of credence in it," Frazier said earlier this week. "So we're just doing the things that are necessary to evaluate our players."

That's hardly breaking news. It's more a reminder that the headliner stars (see: Peterson, Adrian; Allen, Jared) won't put on a uniform. They almost certainly will be joined in the night off by other prominent starters and notable players nursing injuries. Plus those starters who do play likely will finish their night midway through the first half.

Translation: The preseason opener will become a full-on assessment of the bottom half of the roster.

Still, there will be plenty to track. So here's a three-tiered guide for what to watch:

Offense

The obvious story line: Christian Ponder and the first-team offense might only play through the first quarter. So there won't be a huge body of work to judge. But as Ponder stated Wednesday, it's imperative he remain crisp with his fundamentals while continuing to developing a rhythm with receivers. Most of all, Ponder certainly would benefit from reminding local fans of the poise and precision he displayed the last time he played a home game, uncorking a 234-yard, three-TD, zero-turnover effort in a playoff-clinching victory over Green Bay.

Under the microscope: The Vikings stand firmly behind Ponder and believe he'll keep his starting role secure for 16 games. On the outside, however, there's curiosity regarding when, not if, a Ponder-Matt Cassel quarterback debate will mushroom. Cassel will take his first game snaps as a Viking on Friday. In assessing his play, keep the strength of the defense in mind. But it's also a must that the veteran backup be judged on his decisionmaking and ability to move the ball consistently.

Position battle: Write in ink Greg Jennings, Cordarrelle Patterson, Jerome Simpson and Jarius Wright as locks for the 53-man roster. So that leaves only one guaranteed open spot (possibly two) for the other eight Vikings receivers. Joe Webb and Stephen Burton appear to be the front-runners. Chris Summers and Adam Thielen could also make a push in the next few weeks, though they more likely fit as practice squad candidates. Still, Frazier has made it clear that preseason game action will be a heavy determining factor in sorting out the pecking order.

"From a practice standpoint, I think we're where we need to be," Frazier said. "But there's a difference in lining up and playing a game against other competition and different defenses."

Defense

The obvious story line: Rookies, rookies everywhere. First-round pick Xavier Rhodes likely will be held out because of a sore hamstring, though after Wednesday's practice he said he was itching to play. But Rhodes isn't the only draft pick eyeing an emergence under coordinator Alan Williams. Keep an eye on Sharrif Floyd, a defensive tackle with elite quickness off the snap and a knack for being a disruptive force against both the run and the pass. Rookie linebackers Gerald Hodges and Michael Mauti also will see extended time, looking to carve out their niches on defense and special teams.

Under the microscope: The cornerback unit is young, unproven and without a surplus of established depth. Chris Cook, suddenly the group's leader, still is searching for his first career interception. Josh Robinson continues his transition into an unfamiliar role as the top slot corner. And Rhodes knows he will face a steep rookie learning curve. A.J. Jefferson, the team's No. 4 corner, has battled an ankle issue all week. Which means, yes, there's a chance Brandon Burton enters Friday's game as a starter in nickel, with Bobby Felder and Roderick Williams also looking to make a splash. Finding comfort with these corners is going to take time.

Position battle: Erin Henderson will be the opening-day starter at middle linebacker with Chad Greenway beside him on the strong side. But what about the rest of the linebacking depth chart? Marvin Mitchell remains the starter on the weak side as Desmond Bishop (groin) continues dealing with injury difficulties. Mauti faces an uphill battle to overtake Audie Cole as Henderson's backup in the middle. And Larry Dean, a special teams ace, remains listed as the No. 2 on the strong side but might be overtaken soon by Hodges. On pure numbers alone, by month's end, a couple of pretty strong linebackers will be released.

Special teams

The obvious story line: Blair Walsh's introduction to the Mall of America Field fans came by way of a five-field-goal outburst in a preseason victory over Buffalo last year. Walsh went on to become a surprising All-Pro selection. So yeah, punter Jeff Locke, a fifth-round pick, has a tough act to follow in quickly proving himself as a rookie. The left-footer is a diligent worker and has been plenty receptive to coaching during training camp. Now he must find a way surpass the productivity of predecessor Chris Kluwe, a process that takes its next step Friday.

Under the microscope: Don't take Walsh's All-Pro status as a promise for 2013 prosperity. Locke is his new holder, and the field goal operation still isn't quite as smooth timing-wise as coordinator Mike Priefer wants it. During last weekend's under-the-lights practice, Walsh went 7-for-10 during the field goal period, with one of his misses coming as a result of a bad Cullen Loeffler snap. Walsh also made a 42-yarder despite Locke bungling the hold initially. Even after consecutive misses, Walsh finished that period by requesting and crushing a 60-yard attempt. Said Priefer: "He missed two and said let's take it back to 60. That was him the other night, not me. [With] his mental toughness, he doesn't blink."

Position battle: Marcus Sherels remains the top punt returner. But auditions are being held for Stephen Burton, Felder and Wright as well. The Vikings feel secure with Sherels, lauding his ball security and intelligence. But let's face it, in terms of explosion, Devin Hester he is not. So if a suitable successor can be found in a player who might have a more significant role on offense or defense, that's something that will have to be taken into consideration.