Minnesota United isn’t giving away too much ahead of its home opener Sunday at TCF Bank Stadium.

Coach Adrian Heath was mum about what formation he would consider using against fellow expansion side Atlanta United FC and whether some different faces might appear in that lineup from the season-opening 5-1 loss in Portland.

United started with a 4-3-3 and shifted to a 4-2-3-1 in the last 20 minutes of the match, when goal-scorer Christian Ramirez came on as a substitute. That formation seemed a bit more successful in attack, though the Loons did also let in three goals in that time.

In preseason play, the Loons have run a 4-3-3, 4-2-3-1 and 4-4-2.

Ramirez said when he came on against Portland, he talked to Johan Venegas, who had been playing striker. Ramirez told him to feel free to roam wherever he wanted to involve himself in the play because Venegas had been so isolated for most of the match.

“We know [Ramirez is] a goal scorer. Now we have to see, getting him in the team, how it affects the rest of the group,” Heath said. “As I said to the guys … I only pick the team to try to win the game. There’s no hidden agenda in terms of, ‘Oh, I like him more than I like him.’ ”

If Ramirez were to earn the start, it likely would push a midfielder from the lineup. At practice Tuesday, Ramirez, Venegas, Kevin Molino and Bashkim Kadrii seemed to be practicing finishing as the top-four players in the 3-1 part of the 4-2-3-1 formation. Midfielders Collin Martin, Collen Warner, Rasmus Schuller and Mohammed Saeid took turns pairing up and feeding the ball to them as the 2 part of the formation.

Another question around the lineup Sunday is right-back. Heath said the defensive marking against Portland was poor. Left-back Justin Davis said individual mistakes were more the problem than a complete defensive breakdown. Jermaine Taylor played right-back against Portland and struggled. NASL veteran Kevin Venegas has played at right-back in the preseason. If new addition Jerome Thiesson arrives in Minnesota and is fit, he could also play there.

What won’t be surprising is what Atlanta will bring up north.

“Whichever team that they field, I know that they’ll have really quick attacking players because that’s what they’ve gone for,” Heath said. “They’ve gone for speed and spent a lot of money on a lot of really good, young, talented forwards.”

Atlanta will be without midfielder Carlos Carmona, who is suspended after receiving a red card in Atlanta’s opener for stepping on an injured opponent. But Heath said he was actually surprised to not see midfielder Jeff Larentowicz in Atlanta’s first starting lineup and would expect to see him this time.

Atlanta played a 4-2-3-1 in its first match, a 2-1 loss to New York Red Bulls at home.

The two expansion teams have taken decidedly different approaches to building their squads. Most notably, Atlanta made upfront investments to secure three designated players, who command higher salaries. The Loons, taking a more deliberate build-for-the-future strategy, have yet to secure a designated player.

“We’re going about it our own way,” Ramirez said. “At the end of the day, we both have one loss each, and that’s all you can really go by. We know that this is a longer plan, and they’re going for it right out of the gates.”

The teams’ strategies have experts picking Atlanta to finish better than the Loons this season, but Heath said the two clubs still will face the same struggles.

“I don’t care if they spend $50 million, their issues are going to be the same as ours,” Heath said. “They’ve got people coming from different countries, coming to try to settle in America.”

Sunday ticket sales

United has sold more than 32,000 tickets for the home opener and anticipates eclipsing 35,000 for attendance. The stadium’s clear-bag policy and the use of metal-detecting wands will be in effect for the match.