Yes, they carry A & B alternates. They're just above ESPN2 on the channel lineup. I'm almost positive they're 210 and 211. Make sure they're not blocked on your customized channel lineup. There are also alternates on regional sports channels I found after 5 years. Fox Sports Chicago often puts one baseball game on an alternate feed and last year I found the alternates. For Chicago it's 640 most of the time.
Hope that helps but remember.... Subject to Blackouts!