The Union opened their preseason on Tuesday with many holes on their roster left to fill. They can carry up to 31 players, and the signing of centerback Aurélien Collin gave them 23 so far.

Collin’s arrival filled one of the bigger holes. It’s also highly likely that Union academy centerback Ben Ofeimu will sign a pro contract soon, though he could go to Bethlehem Steel.

Ofeimu, 18, cuts an impressive figure at 6-foot-3 and 200 pounds. Manager Jim Curtin lined him up alongside Collin in Monday’s training session, which combined players from the Union and Steel.

Afterward, Curtin said multiple academy products are “close” to signing pro contracts. Asked if Ofeimu is one of them, Curtin gave a knowing look.

“He’s there in terms of the soccer side, that’s what I’ll speak to,” Curtin said. “He’s everything you want in a centerback. The little things, angles and one-on-one duels, can he do a little better on [them] — absolutely. But I’m really happy with the steps he’s taken.”

The Union will also sign another goalkeeper, Carlos Miguel Coronel. He’s a 22-year-old Brazilian from Red Bull Salzburg, Union sporting director Ernst Tanner’s old team. Coronel was on the field with the Union on Tuesday, and the team included him on a preseason roster published Tuesday morning.

Coronel will come in at No. 2 on the depth chart. If, as is expected, Andre Blake is on Jamaica’s national team at this summer’s Concacaf Gold Cup, Coronel will fill in.

Next on Tanner’s shopping list are a left back and a midfield playmaker. The latter signing will fill the hole left by the end of Borek Dockal’s loan spell, but don’t expect the new player to be a like-for-like replacement. The Union intend to vary their playing style from the 4-2-3-1 they adhered to rigidly under Earnie Stewart. As such, the demands on a playmaker may be different.

Tanner has been scouting and negotiating for a while, though it hasn’t all gone as well as he hoped. He initially wanted his deals done by the time the Union leave for Clearwater, Fla., at the end of this week. From the sound of things, that might not happen.

But in a way, it couldn’t have happened no matter what. The window for MLS teams to sign players under contract abroad doesn’t open until Feb. 13. Potential signings would be able to train with the Union before then, but not play in a game.

“We are of course in discussions and we have defined our targets, but sometimes it’s not always going that soft and smooth, and you need to start from scratch again,” Tanner said. “But I think we are in really good discussions now, and hopefully we can present somebody when we go to Clearwater.”