Injuries are threatening to undermine Sussex's Championship challenge.

Jason Lewry is out for a month after tearing a rib muscle and now wicketkeeper Tim Ambrose is a doubt for tomorrow's game against Nottinghamshire at Trent Bridge.

Ambrose suffered slight knee ligament damage when he slipped and fell during Tuesday's National League victory over Durham. He is having intensive treatment but may need to pass a fitness test before the start of play.

Ambrose's fitness is not the only dilemma facing Sussex.

Either Billy Taylor or Paul Hutchison will replace Lewry and they could form the new ball attack if James Kirtley makes his Test debut.

England will not finalise their line-up for the first Test against South Africa at Edgbaston until this morning although it looks likely Kirtley will be overlooked again and can head straight for Trent Bridge.

Director of cricket Peter Moores said: "If James plays it will be difficult to leave either Paul or Billy out, both did brilliantly on Tuesday night and deserve their chance."

Kevin Innes, who scored a century for the second XI yesterday, will only be added to the squad if the county decide to play an extra seamer rather than both spinners.

If Ambrose is ruled out, Mike Yardy is his likely replacement with Matt Prior reverting to wicketkeeping duties.

Sussex (possible): Montgomerie, Goodwin, Cottey, Adams, Ambrose, Martin-Jenkins, Prior, Davis, Mushtaq, Hutchison or Taylor, Kirtley.