Glamorgan will be without seam bowler Graham Wagg for up to 12 weeks after breaking his ankle against Essex.
Originally, the county thought Wagg would be out for six weeks, but he is having surgery on Thursday.
The latest prognosis means the 28-year-old will miss the whole of the Friends Life t20 competition.
"It's a fair chunk of the season which is a massive blow for us," said Matthew Mott, Glamorgan's head of elite performance.
It is all the more disappointing for Glamorgan as Wagg had hit some form with the ball and was their joint leading wicket-taker. He and Huw Waters have taken 23 wickets each in the County Championship.
"With his all-round skills this year with both bat and the ball he has been a different bowler this year to last year," added Mott.
"He is now settled. He is now married and his life was going really well for him.
"He was swinging the ball round corners. He was such a potent weapon for us.
"It's really disappointing for him and for the club he has broken down at this stage. Because in all three formats he was such a massive player."
With Glamorgan losing their opening three Championship matches they find themselves bottom of Division Two.
As well as that they went down in their opening CB 40 game against Hampshire on Bank Holiday Monday.
Though Wagg's injury is a setback Glamorgan are expecting Australia batsman Marcus North to make his debut for them in the 40-over clash with Scotland in Glasgow on Sunday.