[76Texan]

Two things need to be considered:

1. Injury.

If Brisiel played with an ankle injury like he did last year, he wouldn't be any better than Caldwell or Jones (maybe even worse) at the moment.
If Caldwell has been healthy, the O-line would have looked better than it does at the moment.

So in term of RG play, we're not comparing them on the same footing.
Brisiel is playing without injury while Caldwell is playing with several injuries.

2. Continuity on the line.

We expected (or at least the OP should have expected) that in the short term, the lack of continuity on the line doesn't help.
As the year moves along, the line should work better together.

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