Saracens boss Mark McCall has revealed that England number eight Billy Vunipola could face Ulster in Saturday's Heineken Cup quarter-final at Ravenhill.
Vunipola sustained an ankle injury in England's Six Nations clash against Ireland in February and there were fears he would be sidelined until later in the season.
But McCall said he could be fit to return to action this weekend.
"We'll make a decision later in the week," said McCall.
"If Billy plays it'll be because he's fit to play. We won't take a risk with any player."
McCall expects a fierce battle as Ulster host their first European play-off match at the newly expanded Ravenhill.
"They would say it's the biggest home game in their history," he said.
"They've had three away quarter-finals but this is their first home quarter-final and I gather they could have sold out many times over. People are talking of nothing else.
"They're going to be favourites but we'll go with a good plan and will be well prepared."
Ulster also have some injury concerns with Springbok scrum-half Ruan Pienaar battling to overcome a shoulder injury. But Ulster boss Mark Anscombe is optimistic he will be ready to face Sarries.
"Ruan is progressing pretty well, so we are hopeful he'll be all right," Mark Anscombe, the Ulster head coach, told the Times.
"He is a special player. He has a lot of experience, he's a big-match player and he's got the temperament you need in these games to keep your composure."