The problem is that they only know this from practice and in practice, it's unlikely they legitimately gave Rocco the opportunity to get action with the ones.
As we've seen before, the staff often over-values experience and in doing so, the better talent sits on the bench. Look at last year as a perfect example. Joe Alt was the best lineman for us last week. A year ago, he was sitting behind Fisher, Baker and Carmody at LT. We probably wouldn't know how good Alt was if those injuries didn't happen.
Look back to 2014, when Christian Lombard was our starting RT and Mike McGlinchey was sitting on the bench. I'm sure they thought Lombard was one of the best 5 and if Glinch really was, he'd be playing. As we know, the coaches mis-evaluated who were the best 5 and we saw later in the year that McGlinchey should've been playing over Lombard and was CLEARLY one of the best 5.
The coaches have been wrong before and it wouldn't surprise me in the slightest if they're wrong here. Lugg may have experience, but his experience doesn't mean anything when he can't physically play the position he's at at a high enough level.