Mike Zimmer will soon get some answers about a Vikings roster featuring a retooled offense and question marks across the depth chart.

The preseason opener in Buffalo on Thursday night will be a litmus test for how much the team transformed through free agency, the draft and schematic changes. While there are few position competitions to watch on a top-five-ranked defense, the offense, ranked 28th last year in the NFL, will be under the microscope.

Count Zimmer among the curious to see how well rookie running back Dalvin Cook fares behind an overhauled run game, which has new offensive tackles and a revamped zone scheme.

Zimmer declined to say how many plays or series he wants from quarterback Sam Bradford and the other starters, but he said the Vikings may mix and match personnel instead of removing all starters at once.

“Offensively, we’ve been kind of working with the system and exploring some different options and things,” Zimmer said.

The unit’s 2016 failures resulted in an active offseason, including the promotion of Pat Shurmur to coordinator and the additions of new players with millions of dollars and draft picks.

“When we’re in there, I want us to be crisp in and out of the huddle,” Bradford said. “I want us to execute and go down and score. I think that’s what we’re looking for to set the tone for the rest of the preseason going into the season.”

Will Bradford find a new favorite target in receiver Michael Floyd? Can Cook be the home run threat the Vikings anticipate? Is the offensive line finally fixed? Some things were learned during 11 full camp practices, most in pads, but the evaluations eventually grow stale with familiarity and repetition making teammates and plays predictable.

Thursday night against the Bills will be the first, if partial, test. Left tackle Riley Reiff (back), running back Latavius Murray (ankle) and receiver Laquon Treadwell (leg) are not expected to play while recovering from injuries. Injured players often haven’t accompanied the team on preseason road trips under Zimmer. Their debuts are on hold while Cook, Floyd, center Pat Elflein and right tackle Mike Remmers will suit up against a Bills defense whose coordinator is former Vikings head coach Leslie Frazier.

“I think for them, it’ll be good to go against someone else,” Zimmer said. “Because we’re trying to gauge where we’re at, you know? I’m looking forward to it.”

Intrigue on defense starts with Zimmer. Defensive coordinator George Edwards is expected to call plays Thursday as he has been doing during camp practices, while Zimmer assesses how being freed up on the sideline can help him better manage the entire operation.

Otherwise, the Vikings defense has fewer questions, especially after cornerback Xavier Rhodes, nose tackle Linval Joseph and defensive end Everson Griffen signed big extensions.

“The interesting thing is the defensive guys have been together, so we probably could’ve played a game three or four days ago,” Zimmer said.

The most intriguing competition is along the defensive line, where ex-Packer Datone Jones is expected to push veteran Tom Johnson for the starting job at tackle.

Preseason games will also be critical for kickers Kai Forbath and Marshall Koehn, as well as punters Ryan Quigley and Taylor Symmank. In the past, special teams coordinator Mike Priefer has alternated kicks and punts during the preseason.

But the focus remains on offense, for however long Bradford and the starters play before Case Keenum and Taylor Heinicke take over at quarterback.

It can be a short day for the starters, like when the offense took a seat after a 10-play, 96-yard scoring drive during last year’s exhibition opener in Cincinnati.

“Magically after that, we were done,” tight end Kyle Rudolph said. “In the preseason, especially the first preseason game, you want to go out and show everything we’ve been doing throughout OTAs, minicamp, training camp, that you can do it against someone else and not when there are coaches standing on the field with scripted plays.”