The NFL preseason schedule exists in its current form — four games for 30 teams, and five for two — in part as another revenue-generating opportunity for the league, its broadcast partners and its clubs. Results in August, then, are probably of dubious value when starters play only in spurts and teams devote little time to game planning.

For example, starting quarterback Kirk Cousins logged only 71 preseason snaps over the Vikings' first three games before resting during Thursday's finale with the rest of the team's starters. Cousins will likely have full games in the regular season with more snaps than that, and he'll get them after having spent a week preparing for a specific opponent — which the Vikings rarely, if ever, do in the preseason.

Far be it from coach Mike Zimmer, though, to look at a four-game body of work and pass up opportunities for constructive correction. And on Thursday night, as he summed up the preseason, Zimmer groused a bit about how the Vikings played.

"We're excited to get the preseason over with and start focusing on somebody else — start game-planning and see if we can perform better than we have in some of these areas in the preseason."

The Vikings' 3-1 record notwithstanding, they've got some room to improve from how they played in August. They tied for 26th in the league after committing eight false start penalties in the preseason — five of them by an offensive line beset by injuries. They scored only 16 points with the first-team offense on the field; Cousins finished 24 of 40 for 236 yards, and his impressive 1-yard touchdown strike to Stefon Diggs in the first exhibition game would be his only TD pass of the preseason.

And a bumpy month for the Vikings' special teams units continued on Thursday night, when Ryan Quigley had a partially-blocked punt that traveled just 29 yards.

The preseason contained plenty of positive signs for the Vikings. Their efforts to accumulate both stars and depth on defense showed all month, as second-team defensive linemen like Tashawn Bower, Stephen Weatherly and Jaleel Johnson made plays behind the opponent's line of scrimmage.

Linebacker Eric Wilson appeared to take another step forward in his development, playing a bigger role in sub packages and impressing as a pass rusher. And cornerback Holton Hill — whom the Vikings guaranteed $75,000 as an undrafted free agent — stood out more through the preseason, breaking up a pass on Thursday night and returning the second-half kickoff 53 yards.

"I feel like I had one or two good plays. I wish I could have more opportunity to show my ability out there on the defensive side," Hill said Thursday night. "But overall, it was a pretty good game."

The Vikings' biggest roster concern over the weekend figures to be on the offensive line, where center Pat Elflein did not practice in training camp as he returned from offseason shoulder and ankle surgeries. Zimmer said this week he didn't think Elflein would need to open the season on the physically-unable-to-perform list, though there'd seem to be a good chance the team will need to use another center in its regular-season opener against San Francisco on Sept. 9.

Danny Isidora started the game at center on Thursday night, working with Trevor Siemian in the first half before shifting to left guard in the second half. Brett Jones, whom the Vikings acquired in a trade with the Giants this week, swapped spots with Isidora for the second half.

"[Isidora] did great," Siemian said. "He's a smart, smart guy. He was solid with all the calls and everything. We didn't miss a beat there."

The Vikings, who announced Friday the initial 14 players they'll waive, will quickly shift their focus to the regular season, as Cousins makes his debut against his former offensive coordinator (Kyle Shanahan) and a 49ers team that is expected to be better than last season's 6-10 record. From there, the Vikings travel to Green Bay and play three straight games against 2017 playoff teams (the Bills, Rams and Eagles).

They'll rely on a diligent style of preparation that's helped them win 39 regular season games in Zimmer's four years with the team. That, the Vikings expect, will help them buff out the rough spots they hope will be insignificant in the long run.