That's why I put Cork at RB. I'm happy for Chambers to play this season, but I don't want his first game to be away at a team like West Brom. We're going to need good positional awareness and no mistakes to avoid what they did to us last season, and while Chambers is clearly talented his positioning doesn't seem to be the greatest. Cork might not offer much getting forward from RB, but he won't get caught out and he'll provide more support for what is a pretty worrying back line. We know he's got a good record for tackling and interceptions, and he plays a simple passing game. Basically I'm prioritising avoiding mistakes over attacking ability from our fullbacks.
I'm not certain Cork's positioning is that much better though, to be fair. For example I remember against Chelsea in the cup he had an absolute shocker and got caught in behind leading to at least two if not three of their goals, in a similar way to how Chambers has been exposed at times in preseason. I think Cork is a good option to have at RB but not sure he's appreciably better than Chambers to enough of a degree that means he should get the nod ahead of him.