But Miller saw Horvat in an Islanders jersey for the first time Tuesday, when he was watching highlights and saw his former teammate score his first goal with his new team in a 4-0 win against the Seattle Kraken.
"I watched the highlight and I'm like, 'Man, it looks so crazy,'" Miller said.
It will look that way to him live in person too.
"Try our best to stay focused, but there's going to be moments that you can't really believe what you're looking at, him wearing No. 14 over there," Miller said. "We spent every single day together and a lot of time away from the rink on the road.
"The more we treat it to play hard, go at it, maybe not talk at all and go say hi afterwards, I think that's better for both of us."
Maybe that's good advice for Beauvillier, because he too will have a weird feeling Thursday, though nobody is wearing his old No. 18 in New York as of yet.
A first-round pick (No. 28) by the Islanders at the 2015 NHL Draft, Beauvillier knew he was returning quickly after the trade, so he packed lightly. He said his parents and girlfriend would meet him at the Canucks' hotel Thursday to give him more clothes from his home on Long Island.
"It was a weird packing situation, trying to pack light for this road trip and trying to pack heavy for the rest of the season," Beauvillier said. "I've got to get some clothes."
Beauvillier played 457 games for the Islanders and had 209 points (102 goals, 107 assists) for them since debuting in 2016-17. He scored arguably the biggest goal for the franchise in decades, in overtime for a 3-2 win against the Tampa Bay Lightning in Game 6 of the 2021 Stanley Cup Semifinals.
"Every time I start thinking about it, I don't really let myself do it, Beauvillier said. "I'll just try to enjoy the moment. It's the first time I'm going to go through this. It's going to be great to see everyone one last time and then turn the page.
"It's kind of a blessing in disguise that I get to turn the page that quickly. It will be fun, I think."