The call came on a quiet Thursday in late June.

Harper Grant was in the kitchen of their Boston home, making lunch for the kids—Eleanor (eleven), Benjamin (nine), Sophia (seven)—when her phone rang.

Unknown number.

She answered.

“Harper, it’s the GM.”

Her stomach dropped.

In pro hockey, a call from the general manager in the off-season was never casual.

“We’ve been approached by Minnesota,” he said, voice careful. “They want ...