West Bromwich Albion are currently in 13th place in the Premier League table.
Fletcher and Morrison have both featured regularly in the Baggies’ starting line-up, but they could be set for a spell on the sidelines.
Fletcher and Morrison have both picked up injuries in recent weeks, and Pulis admits that it is a blow for his side.
“That’s two very important midfield players for us and two players who’ve been very good this year,” Pulis said.
“We don’t need that. We haven’t got a big enough squad to cope with those sort of injuries.”
Fletcher has been a revelation at the Hawthorns since signing for West Brom from Manchester United.
The Scotland international’s energy and experience has been crucial to the side, and he has put in a series of brilliant displays.
Morrison, meanwhile, has also been a key part of Pulis’ starting line up this term.
The 29-year-old has played 21 times for the Midlands side and he has scored on four occasions.
Morrison’s and Fletcher’s good form has helped the Baggies climb into 13th spot in the Premier League table.