Wales have suffered four withdrawals for the upcoming World Cup qualifiers against Liechtenstein and Germany.
Cardiff winger Joe Ledley, Nottingham Forest striker Robert Earnshaw, Coventry forward Freddy Eastwood and Doncaster's Brian Stock have all been forced to pull out through injury.
Ledley sustained a hamstring injury in Cardiff's 1-1 draw with Blackpool and scans have shown he has suffered a tear.
Stock has been struggling with a back problem for some time and he has not joined up with the rest of the squad.
Earnshaw missed Nottingham Forest's weekend's defeat Crystal Palace Saturday with a hamstring problem.
Eastwood sustained knee and ankle problems in Coventry's win over Southampton and he will return to his club for treatment on the knocks.