HULL KR head coach Tim Sheens fears prop Ryan Lannon could be out for up to 10 weeks.
The promising forward, 23, had just begun to start making his mark having switched from Salford City Reds last autumn.
However, after suffering the injury at Castleford Tigers last week, he could now be absent for some time, putting more pressure on depleted Rovers for Sunday’s trip to Wakefield Trinity.
“The scan shows syndesmosis, a splitting of the bones in the foot,” said Sheens.
“We’ve another X-ray yet and it could be a month or five weeks but, if it is what we think it is, it could be ten weeks.
“It is a blow; he’s a young pair of legs and he has a lot of ability.
“We have him on a three-year deal but he’s not happy about the injury because a number of the senior guys are down; it would have been a great chance for him to cement himself a spot.”
Rovers - who have lost their last two games - are already without experienced prop Nick Scruton while England front-row Robbie Mulhern faces a fitness test on his injured calf on Saturday.
“It’s common knowledge that last week we finished at Castleford with no-one on the bench, only a 13,” added Sheens, who may bring young winger Will Oakes into his squad on Sunday.
“We are struggling a bit for numbers. It’ll be Saturday before I get confirmation on guys like Kane Linnett and Robbie Mulhern for instance while Jimmy Keinhorst will have his head test then, too.
“At this stage I think George Lawler will be back but we’ll wait and see how he pulls up. “It’s one step forward and two steps back in that regard.”
In more positive news, however, former Robins captain Shaun Lunt is nearing his comeback.
The ex-England hooker has been missing since being hospitalised with blood poisoning in September following an infected abscess on his spine.
Sheens said: “I think Shaun Lunt could return against Catalans next weekend and we get back our skipper Joel Tomkins too.
“We still have a competitive group out there but we’re looking a bit skinny on the bench.
“At some stage hopefully we’ll have our dream team out on the field.”