Hampshire have put Alan Mullally's Championship debut for them on hold after he picked up a rib injury prior to Somerset's visit to Southampton today.
The Australian leg-spinner Shane Warne does make his Championship bow, however, after his presence helped draw almost 3,000 fans to Northlands Road for Monday's National League defeat to Warwickshire.
The veteran medium pacer Peter Hartley will have a late fitness test on his recurring hip injury, while Alex Morris is in line to make his first Championship appearance for 11 months after recovering from a long-term shin injury.
Somerset's only injury doubt is Mark Lathwell, who has been troubled by hamstring trouble and missed last week's season-opening match with Surrey.
Somerset's captain, Jamie Cox, said: "Hampshire will be a good side. Warne's influence will only make them better."
John Crawley is back from his thumb injury as Lancashire tackle Leicestershire at Old Trafford, but Derbyshire are without their captain, Dominic Cork, as they travel to Headingley to meet Yorkshire.
Cork is out with a badly injured knee. Leicestershire's cricket manager, Colin Wells, said: "Yorkshire are a hard, competitive side. But we feel we still have the squad capable of doing very well at Headingley, and that's what we intend to do."
Essex and Nottinghamshire have no new injury worries for their Chelmsford fixture, and Northamptonshire's Paul Taylor is still struggling with a knee problem against Middlesex at Lord's. The home side's coach, Mike Gatting, brings in Andrew Strauss for Mike Roseberry.
* The MCC faces protests at today's annual general meeting from angry members who were charged to watch last summer's World Cup matches at Lord's. They have put a proposal before the AGM questioning the committee's right to take action without consultation with the membership.Reuse content