He didn't physically practice during training camp, pre-season or the first 4 weeks of the regular season.
However, he didn't just arrive from Siberia.
He was here and physically practiced in OTAs and Mini Camp. He had three practices in which he participated over the past several days.
He's had a playbook in his hands for about 8 months now. He's had plenty of time to study, observe, watch film, and ask questions.
Simply put, he must not be a 100% as of right now. Disappointing, but better to hold him out another week instead of taking a chance of getting reinjured.
There's also the possibility the Saints didn't want to cut and expose another player or put someone on IR yet in order to activate Miller.
Hopefully he's a full go with fresh legs Sunday against the Bucs. The Saints play 3 games in 10 days. They may not need him tonight, but they will the next 2 games.