Centre Eoin Griffin, who pulled up in the warm-up at Stadio di Monigo last Friday night, was replaced ten minutes before kick-off by Brian Murphy.
The 23-year-old Griffin is awaiting the results of a scan on a torn foot ligament but is likely to be sidelined for up to five weeks.
Also added to the injury list were tighthead props Ronan Loughney (concussion) and Nathan White (calf). Both players are doubtful for this week's Heineken Cup opener against English Premiership side Saracens.
In better news, Connacht's most-capped player Michael Swift, who missed the Treviso game, returned to training yesterday and is available for selection this week.
Out-half Craig Ronaldson has also returned to the fray and is in the mix ahead of Thursday afternoon's team announcement.
Last Saturday saw both David McSharry and Denis Buckley return to club rugby for the first time this season, playing a part in Ulster Bank League wins for UCD and Corinthians respectively.
The Connacht v Saracens match is on course to be a sell-out with both the Clan Terrace and Enclosed Stand now sold out.
Remaining tickets are on sale from tickets.ie, the Connacht Rugby office and Centra and SuperValu stores province-wide.