Glasgow lock Tim Swinson will miss Sunday's European Champions Cup quarter-final against Saracens after his red card against Connacht was upheld.
Warriors challenged the card, which was handed out for using a swinging arm in a tackle on Dave Heffernan during Glasgow's 35-24 Guinness PRO12 win last weekend.
But a PRO12 disciplinary panel in Neath backed referee Ian Davies' decision and ruled in-form Scotland international Swinson would be suspended for four weeks.
A statement read: "The foul play merited a mid-range entry point which carries a suspension of six weeks.
"There were no off-field aggravating factors but after considering mitigating factors, the committee reduced the final suspension to four weeks.
"The ban was therefore reduced by two weeks leaving the player free to resume playing on Monday, April 24, 2017. He was reminded of his right to appeal."