Middlesex bowler James Harris has been ruled out for another two weeks because of his troublesome hamstring.
Harris has missed the last two weeks because the injury, sustained in the Division One victory over Nottinghamshire.
He played against Cambridge UCCE last week and again against the Unicorns in a 40-over game at Wormsley on Sunday.
But he complained about pain in that match and he has been told to rest for two weeks.
The injury potentially reduces his chances of being selected for England's Champions Trophy squad, which will be unveiled later this month ahead of the June tournament.
Middlesex boss Angus Fraser told the club website: "Everybody at the club feels sorry for James who is desperate to get his time at Middlesex off and running.
"But we are all confident that this is just a minor setback and that he will have a major role to play in our season as it develops. At the moment we have the fast bowling resources to cope with James' injury and it will be great to get him back fully fit for when Steven Finn departs for England duty."