Ospreys could be without three of their star names, including Wales captain Alun Wyn Jones, for the rest of the season.
Jones suffered a knee ligament injury during the 25-7 win over Ireland which sealed Wales' Grand Slam success, while George North fractured two metacarpals in his left hand in the same game.
They have only been given a chance of returning from their respective injuries for the season finale - Judgement Day - against rivals Cardiff Blues on April 27.
Before then, Ospreys take on Dragons on Saturday and then head to South Africa to play the Cheetahs on April 6 and Southern Kings on April 12.
Ospreys also revealed on Friday that centre Scott Williams, who missed the Six Nations with a disc problem in his lower back, is almost certainly out for the rest of the season.
An injury update from the Guinness Pro14 team read: "Alun Wyn suffered knee ligament damage last weekend and is currently rehabbing.
"He won't travel to South Africa with the squad at the start of April but at this stage we haven't ruled him out of the Judgement Day game against Cardiff Blues.
"George fractured two metacarpals in his left hand early in the Ireland match.
"Having seen a specialist this week, he needs time for the bones to heal but we are optimistic about the potential for him to be involved on Judgement Day.
"Scott is recovering from the disc problem in his lower back which kept him out of the Six Nations.
"He is progressing well but we aren't expecting to see him back representing the Ospreys before the end of the season. He will continue his rehabilitation into pre-season with the goal of making himself available for the Rugby World Cup."