Ireland full-back Rob Kearney will see a specialist shortly to ascertain the extent of the damage done to his shoulder.
The review of a scan was inconclusive and has prompted further investigation.
It is believed Kearney (below) felt the full force of a hard blow from Australian wing Henry Speight as he countered down the right touchline on Saturday.
It must place in doubt his availability for the back-to-back rounds three and four of Leinster's Rugby Champions Cup away to Harlequins (December 7) and at home to Conor O'Shea's club at The Aviva Stadium (December 13).
It comes at a time in his career where he appears to be right back to his best under the combined efforts of Matt O'Connor and Joe Schmidt.
His younger brother, Dave, made a welcome return to the game from a serious knee injury against Benetton Treviso on Sunday.
It was there Luke Fitzgerald was forced to withdraw late with a twinge to his thigh/groin that could spell the return of the problem that kept him out for the start of the season.
Hooker Richardt Strauss's hamstring tightened up to see him replaced in the 37th minute of the same game.
Meanwhile, following Connacht's 40-point win over Zebre on Friday night, Pat Lam's squad were back to full training yesterday as they prepare for the second of three back-to-back home games with Scarlets, the visitors on Saturday.
Hooker Jason Harris-Wright was the only major injury concern from the last round of PRO12 action.
The 26-year-old was replaced just before the half hour mark after going down at the Sportsground with an injury to his right knee. An MRI is scheduled to determine the extent of the damage.