nfldraftscout.com has your man Leonardo Bates ranked #57 out of OT prospects.
They have Gaines and Marquardt as #22 and #23 respectively. That seems like 6-7th round territory to me.
Mr Bates will more likely than not be an UDFA. But hey, we've had some great luck with undrafted players!
"I am easily satisfied with the very best." -- Winston Churchill (and most of SR sometimes)