Thomas was shown the red card by English official Dave Pearson in the last minute of their 38-17 Heineken Cup defeat at Castres on Saturday night.
The suspension, reduced from four weeks after Reggiardo spoke on Thomas’ behalf at the disciplinary meeting, also means Thomas will miss the Ospreys European clash against Munster at Neath next Sunday.
At the hearing Thomas explained that he was having difficulty breathing because Reggiardo was pulling on the collar of his jersey, but insisted h e was sorry for the offence.
It rounded off a miserable weekend for the Ospreys and Welsh rugby with all four regions losing on the opening round of games in the Heineken Cup.
