To me it says that the coaches are confident that Penning can get to where they want him to be, otherwise they would have done more to shore up the position. At least that's the only justification that I can come up with.
I think they were confident back then, but giving Udoh half of the 1st team reps at RT the last two days tells me that their confidence that he will be ready to start in waning and they are close to making a change.
And I think it was a risky move that I hope doesn't blow up in their face.