Mohamed Sanu says Christian Wade needs to adapt quickly if he is to make a successful switch from rugby union to the NFL.
Judicael Cancoriet is set to have surgery on a torn pectoral tendon but could still return for the Top 14 playoffs.
Former Wales prop Ceri Jones will keep hold of the reins at Pro14 side the Dragons for the remainder of the season.
Premiership champions Saracens are through to the last eight of the European Champions Cup after beating Lyon on Sunday.
Wales are set to have Taulupe Faletau available for the Six Nations, while Jonathan Joseph may be available for England.
Ryan Mills' last-gasp drop goal put Worcester Warriors into the last eight of the Challenge Cup for the first time in a decade.
All four Pro14 sides in European Rugby Champions Cup action on Saturday secured victories, three coming against French opposition.
Zebre led at half-time of their European Challenge Cup match at La Rochelle, but the hosts fought back in stunning fashion on Friday.
Joey Carbery, Rory Scannell, Keith Earls and Andrew Conway were among the tries as Munster overpowered Gloucester.
Returning to action after a broken arm proved an anxious experience for Saracens' Billy Vunipola, who is steadily regaining his poise.
Bill Beaumont, chairman of World Rugby, hailed the progress made on injury-prevention in the sport but acknowledged more needs to be done.
Three weeks before the start of the Six Nations, Sam Underhill has been ruled out of the tournament in a significant blow to England.
Two-time World Rugby Player of the year Beauden Barrett says John Plumtree has the potential to coach the All Blacks.
Clermont Auvergne hammered fellow title hopefuls La Rochelle, who had won 10 of their previous 11 matches.
Wasps won for only the second time since September with a fit-again Joe Launchbury back in the side.
Zebre were no match for Pro14 rivals Cheetahs on Sunday as the South African side eased to a bonus-point victory on the road.