Bundee Aki makes his return from injury as Connacht tackle Treviso while third-placed Ospreys host Glasgow Warriors.
New Zealand-born flanker Callum Gibbins will join Glasgow on a three-year deal ahead of the 2017-18 Guinness PRO12 season.
Stuart Barnes on a great Sunday for the Premiership's northern clubs and concerns for Test rugby in the southern hemisphere.
Ulster registered a second bonus-point win in succession over Scottish sides when they defeated a weakened Glasgow 37-17.
Gregor Townsend believes Ali Price and Henry Pyrgos are ready to fill in for injured Scotland captain Greig Laidlaw.
Scotland international Peter Horne has signed a new three-year contract with Glasgow Warriors.
Scotland prop Zander Fagerson thinks proposals to squeeze the Six Nations into a four-week window are "ridiculous".
Glasgow Warriors have signed South African prop Oli Kebble from Super Rugby side Stormers.
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