In his 290 career games before signing with the Oilers, Brown has been ranked the third worst defenceman by xGF%. The analytics matched the eye test - it just wasn't great. Between Brown buying a house in Edmonton and admitting this contract was a mistake before game one, it was surely a double decision for the Oilers - but it's undoubtedly the right one. The Oilers will be a better team without Brown, and they can bury his entire salary in the minors. Not only that, but players need to make the team based on merit and not their contracts.
It's certainly tough to cut ties with a free agent signing before even one game, but the Oilers made the right decision on all accounts. Every roster spot will matter for a team making a push for the Stanley Cup, and to ice the best possible lineup every night.