Yorkshire are waiting to hear if batsman Aaron Finch's arrival will be delayed after he was injured during an Indian Premier League match.
The Mumbai Indians player, 28, was forced to retire hurt after pulling his hamstring while going for a single against Rajasthan Royals on Tuesday.
Finch is set to play for the Division One champions after the end of the IPL.
But the Australian tweeted that scans revealed damage that is likely to rule him out for the rest of the tournament.
The World Cup winner is expected to play for Yorkshire in all competitions this season having made five appearances in the County Championship last season, scoring 291 runs at an average of 48.5.
Finch also starred for the Vikings in last season's T20 Blast, hitting 256 runs in 10 innings, with a high-score of 89 - although the county failed to make the knockout stages of the competition.