Chris Seddon definitely won't start Thursday. The Rays won't immediately put him on waivers. It's up in the air as to who will start Thursday for Montgomery, but Derek Feldkamp is who I'd expect. He was in the rotation earlier this season.
Since Durham is now down a catcher, the Bulls have to add one. Not sure on that front, but it does NOT look like John Jaso is leaving. The Biscuits already have Josh Arhart on the disabled list and Matt Spring is here from Columbus while he recovers. The Rays could sign somebody for the Durham slot or push someone up from Vero Beach.