JASON Gillespie has labelled the majority of Yorkshire's NatWest T20 Blast campaign as unacceptable.

The White Rose coach has promised a rethink in their strategy when it comes to the game's shortest format, having seen the Vikings win only four of 13 North Division matches.

Yorkshire round off a forgettable tournament with a home match against reigning champions and this season's North Division winners Birmingham Bears at Headingley tonight.

The Bears inflicted one of eight defeats upon Gillespie's side at Edgbaston last month, when Yorkshire could only post a meagre 132-7 and lost by six wickets with eight balls to spare.

"We've been poor," admitted Gillespie, who has now seen Yorkshire fail to get out of their group in three of four seasons since he arrived at Headingley ahead of 2012.

"Our senior players haven't stepped up to the plate and done the job. Our best bowler has been a 17-year-old seamer, our frontline batsmen haven't really fired and our experienced bowlers haven't fired.

"It's something we are going to be looking at moving forward because it's unacceptable and we need to play better.

"We pride ourselves on the standards we set – and the standards we've had in T20 cricket simply haven't been good enough. We need a bit of a rethink on how we go about it and that will all happen in due course.

"We've been disappointing and we all know that. We haven't had a settled side but that's certainly not an excuse, it's just a fact.

"The key areas for us have been our up-front bowling and at the end of an innings as well as our consistency with the bat. Young Matt Fisher has been outstanding. He's been our best bowler at the death."

Yorkshire have lost four out of their last five North Division fixtures, with the odd one out a win over Durham at Headingley thanks to Jonny Bairstow's stunning 92 which helped them recover from 66-4 to chase down 192.

Finishing on a high tonight will be no easy task for the young Vikings, given that Birmingham should include New Zealand superstar Brendon McCullum at the top of their batting order.

Gillespie said: "We look to win every game we play and that doesn't change.

"People question us when we leave players out, especially if there is a Championship game starting the next day or a couple of days later.

"We want to win every game but you can't play 11 players across all three forms – that's just not going to happen. There's not one team in the country that does that.

"We have to have a squad mentality and we've had changes in personnel in Championship cricket as well as T20. We can't blame that."

Ashes batsman Bairstow has been replaced by Andrew Hodd in an otherwise unchanged 13-man squad from last week's defeat against Northamptonshire at Wantage Road.

Hodd will take the gloves but Gillespie has yet to decide who will take over the captaincy. Alex Lees captained Yorkshire in the opening Championship match of the season and a pre-season Twenty20 tournament in Dubai.

Birmingham have won all five previous T20 meetings between the two counties.

Yorkshire (from): Carver, Coad, Craddock, Fisher, Gibson, Hodd, Leaning, Lees, Maxwell, Plunkett, Rhodes, Wainman, Waite.