YORKSHIRE face a defining eight days in their NatWest T20 Blast campaign, with Jason Gillespie insisting his players have what it takes to hoist themselves into quarter-final contention.

The Vikings have three North Group games between tonight and next Friday, with the first of them against Birmingham Bears at Headingley.

They then travel to Derbyshire on Sunday and Nottinghamshire next week knowing they can ill-afford a slip-up, given a run of only two wins in eight games so far.

Gillespie's troops currently sit second bottom in the table – but four wins in their last five completed limited-overs matches have raised hopes of a revival just in the nick of time.

Yorkshire coach Gillespie insisted: "Absolutely, I still think we can qualify. You've got to have that attitude, in my opinion. If you don't, your chances are next to nil.

"We have the squad, the players, the desire and they are pretty decent ingredients. We know we need to win games but there's no magic bullet; no secret formula.

"Win is the operative word but the key for us is having our focus on what is going to allow us to win, as opposed to that end result.

"We can talk all we want but I don't think we've scored enough runs or bowled well enough so far."

Yorkshire will be without new overseas recruit Travis Head tonight as he is only due to arrive from Australia tomorrow ahead of an expected debut at Notts.

But the Vikings have been boosted by the return of England limited-overs trio Liam Plunkett, Adil Rashid and David Willey from international duty against Sri Lanka.

Gary Ballance, selected yesterday in England's Test squad for next week's series opener against Pakistan at Lord's, is also included in a 14-man squad for tonight and Sunday.

"If we can get two wins, we will find ourselves in a decent position," said Yorkshire limited-overs captain Alex Lees.

It was initially hoped that explosive left-hander Head would arrive in time to debut in tonight's match.

But Gillespie, who knows the South Australia captain well from their time together with Adelaide Strikers over the most recent winter, revealed: "Travis will arrive on Saturday, so he won't be playing Sunday.

"But he will be with us during the week at The Oval (where Yorkshire are in County Championship action against Surrey from Monday). He can have a net there and he can get to know his team-mates a bit.

"There is the potential for Travis and Kane Williamson to play together before Kane leaves for New Zealand, so that is exciting.

"Travis will be here until the end of August and then we'll see what happens.

"We do have scope to have him around for the rest of the season but at the moment he's here until the end of August. He is an impressive lad and, in time, you will come to see that."

Birmingham, the 2014 champions, currently sit second in the North Group table with five wins from their eight T20 Blast matches.

They are expected to hand a debut to Australian wicketkeeper Matthew Wade, who has been signed to replace New Zealander Luke Ronchi.

Yorkshire (v Birmingham and Derbyshire): from Lees (c), Ballance, Bresnan, Coad, Hodd (w), Leaning, Lyth, Patterson, Plunkett, Rafiq, Rashid, Rhodes, Willey, Williamson.