Connacht centre Mark McHugh was stretchered off in Friday's 22-17 friendly win over Leicester Tigers with a knee injury. He is expected to be out of action until next spring.
McHugh scored a crucial try and kicked a trademark 40-metre penalty in the pre-season victory, but an incident in the closing stages, in which the 27-year-old was caught late as he bulleted a clearance kick away, has wrecked his season.
McHugh, capped by Ireland against Tonga two years ago, was taken to hospital with his injury subsequently confirmed as severed lateral knee ligaments. Surgery has been set aside for the centre later this week.
Connacht coach Michael Bradley, who expects to be without McHugh for five to seven months, said: "It is a terrible blow for Mark personally and for the team in general. He had a great pre-season campaign and was in top shape.
"But Mark is a very positive guy, a quality professional and he will work very hard to be back on the pitch as soon as he can."