Australian batsman Damien Martyn makes his debut for Yorkshire in their championship match with Somerset starting at Headingley tomorrow and Undercliffe opener Chris Taylor is also given the chance to lay down his credentials.

Martyn was hit by a sickness bug immediately upon his arrival in Leeds on Saturday and was unable to play in the National League game against Surrey Lions at Headingley the following day but he is now fit again and netting with his county colleagues.

With New Zealand captain Stephen Fleming and Indian left-hander Yuvraj Singh having returned home, room exists to give Taylor his first championship outing since the first match of the season when he was unfortunate enough to be the only batsman to miss out as Yorkshire racked up 673 for eight declared off Northamptonshire's flagging attack.

Taylor has shown a sound technique and strong powers of concentration in his eight first class matches so far but he still lacks a really big score and he needs at least one of these before the end of the season if he is to feel confident about a new contract.

Darren Gough and Matthew Hoggard are both named in Yorkshire's squad of 13 and Craig White returns after recovering from back spasms but Ryan Sidebottom's comeback following a sprained ankle is further delayed because of a heavy cold.

Yorkshire are 18-and-a-half points behind third-placed Glamorgan with a game in hand and nothing less than a win will do against Somerset if they are to keep alive their slender hopes of promotion.

They then take on Worcestershire at New Road before their final match against Gloucestershire at Headingley and they cannot afford to slip up in either of them.

Things are just as tough in the National League where they need to win all three of their remaining matches to stand any chance of avoiding relegation.

"We have got the equivalent of three Test matches and three one-day internationals coming up and now is the time for everyone to stand up and be counted," said director of cricket, Geoff Cope.

Yorkshire (v Somerset) from: Wood, Taylor, McGrath, Lumb, Martyn, White, Blakey, Dawson, Gough, Silverwood, Hoggard, Kirby, Craven.