Worcestershire Director Of Cricket Steve Rhodes says the current busy international schedule means it will "not be easy" to find an overseas replacement for South African paceman Kyle Abbott.
Abbott played the last game of his current spell with the County against Kent in the Specsavers County Championship defeat at Canterbury.
His time at New Road has been cut short because of the Proteas forthcoming Test series against New Zealand – and all of the other leading nations are also currently in action.
The West Indies and India are half-way through a four Test series in the Caribbean which will be followed by two T20Is.
Sri Lanka and visiting Australia have one Test left to play before starting an ODI series and Pakistan are touring England.
Rhodes started the search to see if anyone will be available as soon as it became clear Abbott would be leaving but he admitted: "It is not easy at all (finding a replacement) at this late stage of the season.
"If you look at the international calendar, a lot of teams are playing but we will do our best to try and get an overseas player."
Rhodes remains optimistic opening batsman-spinner Brett D'Oliveira will be fit to return for the Specsavers County Championship match with Glamorgan at New Road starting on Saturday.
D'Oliveira suffered a dislocated finger in the Royal London One-Day Cup clash with Nottinghamshire at Trent Bridge and was ruled out of the Kent match.
Rhodes said: "Brett had a dislocation and a little cut and, the way things are looking, he is on track for playing the next game."