I don't closely follow Alabama, so I can't confirm, but reports indicate that Sark was the heir apparent at Bama before heading to Texas.
Makes me wonder if Saban was simply biding his time until Sark had a successful year before stepping down. Saban undoubtedly bolstered Sark's leverage with the Texas administration by choosing a time when Sarkisian's appeal to Alabama is at an all-time high.
Regardless, Sark's in line for a hefty payday, whichever way things shake out.
I think Texas locks down Sark and DeBoer ends up being the guy at Bama. I'm just guessing though.