Bally Sports is supported on Roku, but Bally Sports+ (streaming service) isn't supported yet, and wont be until the Bally Sports app is updated/enabled in mid-July:
"At launch, consumers were able use the new regional sports network (RSN) streaming service on Apple TV, Amazon Fire TV, Android TV, iOS, and Android; it is expected to come to Roku devices in mid-July."
https://thestreamable.com/news/bally-sports-plus-launches-on-apple-tv-fire-tv-android-tv-and-more
So, as DBDukes stated, keep checking for app updates, once the BS+ service login appears within the BS app, you'll be able to stream BS+ on Roku.
