Jamie Heaslip gave Ireland coach Joe Schmidt a Six Nations fitness scare after suffering a head injury during Leinster's 22-9 win over Ospreys in the PRO12.
The Irish region moved three points clear of Scarlets at the top of the PRO12 table with victory in Swansea, but their joy was tempered as their No.8 and centre Luke Fitzgerald limped off with head and shoulder injuries respectively.
Heaslip had blood coming from his mouth as he left the field and was not allowed back on having failed a head injury assessment. Ireland open their Six Nations campaign against Wales on Feb. 7, putting the forward's involvement in some doubt.
Despite losing Heaslip, and falling behind to Dan Biggar's early drop goal, Leinster sealed victory thanks to a brace of tries from Dave Kearney, and another for Noel Reid.
Visiting fly-half Johnny Sexton kicked seven points, while opposite number Biggar contributed all of the Ospreys' nine points.
Elsewhere, Edinburgh moved joint-second with an uninspiring 28-13 win which leaves Treviso rooted to the bottom of the standings and without a win away from home for 13 months.
After a blistering opening quarter of an hour that saw Edinburgh leading 10-0 thanks to a try from Damien Hoyland and the conversion and a penalty from Sam Hidalgo-Clyne, the first half fell away.
Two penalties from James Ambrosini kept Treviso in it and Edinburgh went in at half-time leading only 10-6.
From the restart a penalty from Hidalgo-Clyne followed by a penalty try converted by the Scotland international put Edinburgh into a 23-6 lead.
However they were unable to build on that or deal with the Treviso driven line-out which produced a try for Robert Barbieri -- converted by Barbieri -- and came very close to producing a second touch-down.
However a second try from man-of-the-match Hoyland in the final act saw Edinburgh home and move level on points Scarlets, who play Connacht on Sunday.