The season opener looms in five days, but Harrison Smith could only shrug when asked which of his fellow safeties will line up next to him against the St. Louis Rams.

Since the start of training camp, Smith has patrolled the back end of the Vikings secondary with Robert Blanton, Jamarca Sanford, Chris Crocker, Kurt Coleman, Andrew Sendejo and Mistral Raymond at different points. Three of those safeties started a game in the preseason.

But after this week's roster cuts, only Blanton, Sendejo and rookie Antone Exum still are standing, and coach Mike Zimmer hasn't decided who will start alongside Smith going forward.

"I've worked with every guy in the locker room since training camp started, so I think there's a good vibe among all of us," Smith said, downplaying any questions about chemistry in the secondary.

"As long as we communicate and we're all on the same page, we should be in the right spots."

While the competition at safety — complicated by injuries to Sanford, Blanton and Sendejo — was wide open in training camp, it appeared that Crocker, who had played for Zimmer the past seven seasons in Atlanta and Cincinnati, was the favorite, if there was one, to start.

So much for that.

Crocker and Coleman, who both had starting experience elsewhere, were sent packing as the Vikings trimmed their roster to 53 players Saturday. And Sanford, who was also in jeopardy despite starting next to Smith in both 2012 and 2013, was placed on injured reserve.

"We felt like we had a lot of the same guys," Zimmer said. "Special teams had a lot of influence on it."

Blanton and Sendejo were among the team's leading tacklers on special teams a year ago, and Zimmer said the Vikings are pleased with Exum's growth in that phase.

But one of those three will have to start on defense, too, and it's not as if any of them have seized the position.

Blanton was with the first-team defense during spring workouts and at the start of training camp, but he missed two weeks because of a hamstring injury, putting the position into further chaos.

While he was out, Sendejo returned from a back injury. When finally healthy, both did enough to convince Zimmer to cut ties with three veteran safeties.

"They had a tough decision upstairs, and I just have to come out and do my job and worry about getting better," said Blanton.

Zimmer said this week's practices will determine who starts.

Blanton, who played cornerback at Notre Dame, seems to fit what he is looking for at the position. He has some man-to-man coverage ability and is the rangiest safety of the bunch.

"Sometimes when you make the transition from corner to safety, it takes those guys a while," Zimmer said. "He's a smart guy and does that. You have a little more athletic ability usually when you bring a corner in there. Unfortunately, he got hurt early, and we didn't get a chance to see him a little bit more."

Zimmer spoke this spring about the challenge of evaluating safeties for today's NFL and said that in the past he thought about playing three cornerbacks and just one safety in his base defense.

Like Blanton, Exum also lined up at cornerback in college, and Zimmer also hinted that he could eventually move cornerback Shaun Prater to safety as well.

Finding another safety who could match up with receivers or cover a lot of ground as a zone defender would allow Zimmer to use Smith closer to the line of scrimmage, where at times he wreaked havoc during the preseason, particularly as a blitzer off the edge.

Smith said he is confident that whoever starts next to him in St. Louis will be able to do the job.

"They've all made plays. They're all competitors. They all can tackle. They all can run. They're smart guys," Smith said.

"I played with Robert in college for a while. I've been with Sendejo here. And Exum is a young guy with a lot of talent. Those guys have done a lot of good things."