This is from the article:
The Supreme Court said it rejected the appeal in an order issued on the first day of its new term. The court rejected about 1,800 appeals that had piled up during their summer recess.
One of the first orders of business for a new court term is to decide which cases to take, which IIRC requires four votes. (Someone else may know better about the number.) So presumably this is one of the first cases that didn't make the cut. Which would mean Justice Roberts participated, but we don't know whether he voted to hear the appeal or not.
I said this, and wanted to correct it, because I found out yesterday I was wrong. I read that the refusal to hear the appeal was actually voted on before Roberts took office, and they just waited until the first day of the new term to announce it.