If the charge that Ubogu verbally abused the referee Alun Ware is proved, then a suspension of up to 120 days can be imposed. The recommended maximum four-month punishment would leave him on the sidelines until mid-March.
The RFU management board decided he must attend the hearing, even though officials from both clubs conducted their own investigation and unanimously agreed that Ubogu's red card was sufficient punishment.
Announcing the Twickenham inquiry, the RFU's chief executive, Francis Baron, said: "It is very important that any England player is disciplined, irrespective of the nature of the match, if it's appropriate to do so."
Ubogu remains the only player sent off in the cross-border matches featuring Welsh rebels Cardiff and Swansea against England's Premiership clubs. The games are controlled by independent officials, because neither the RFU nor the Welsh Rugby Union will recognise them and appoint referees or touch judges.
On this occasion, the RFU requested a copy of the referee's report, which was provided by Ware even though Twickenham has no jurisdiction over him.
Any significant period of suspension could seriously harm Bath's Premiership title prospects prior to a demanding pre-Christmas schedule against Harlequins, Northampton and Saracens.
Ubogu's fellow tight head, John Mallett, has been unfit through injury since early October, while Chris Horsman recently started a new course of cancer treatment.
It would leave only Dave Hilton and Kevin Yates of the recognised standard available, giving Bath little option but to explore rugby union's temperamental transfer market.
The Bath coach, Andy Robinson, was so incensed with events at the Arms Park that he considered not sending his players out for the second half of a game won 24-3 by Cardiff.
The Saracens forward Troy Coker is also in the dock tonight after being sent off for punching the Newcastle prop Ian Peel. The Australian international was dismissed by the referee, Chris White, as Saracens lost 43-12 at Gateshead almost three weeks ago.
A probable 30-day ban would rule him out of Premiership games against Gloucester, London Irish and Bath.
Welsh rugby was celebrating on Tuesday night after Scott Quinnell was freed to play against Argentina this weekend. Quinnell won his appeal against a 14-day suspension imposed for a late tackle on Wasps' Lawrence Dallaglio. The back-row forward can now appear in Saturday's Test against the Pumas at Stradey Park, Llanelli.Reuse content