Yorkshire are still unsure as to how long they will have Mitchell Starc as their overseas player for.

The White Rose county are in dialogue with Cricket Australia about the 22-year-old's availability ahead of and during his country's A tour of England, which runs between July 27 and August 17.

Starc is hopeful of being allowed to remain at Headingley until a 17-man A squad arrives on English soil instead of having to return Down Under for any potential training camps.

But, as yet, nothing has been confirmed ahead of the start of the Friends Life t20 competition on June 15.

Australia A's tour includes two three-day matches against Derbyshire and Durham before two four-day matches against the England Lions at Old Trafford and Edgbaston, which have been labelled as unofficial Test matches.

Their squad also includes pacemen such as Mitchell Johnson, Patrick Cummins, James Pattinson and Ben Cutting, and there is no guarantee that Starc will see regular match action despite having been in Australia's full squad for their recent tour of the West Indies.

Starc will play in Yorkshire's County Championship match against Glamorgan at Colwyn Bay tomorrow.

White Rose skipper Andrew Gale said: "We're just waiting on Australia to see exactly what's going on with their A tour. The bottom line is that we're trying to get Mitchell for as many games as we can.

"I think he'll probably be here for the first part of Twenty20 at least.

"They are bringing a massive squad over, and there's no point him carrying drinks for them if he can play for us. He'll get more experience playing for us than he would playing for Australia A. That's my opinion.

"There's games against Durham and Derby, and I know they won't put their strongest team out against Australia A, certainly not in July and August when there's a lot of cricket to be played in the three competitions.

"They'll be resting their better players. Surely he'd be better playing for us against full strength teams, which is tough, hard cricket."

During the Aussie tour, Yorkshire play three Championship and three 40-over matches alongside a potential Twenty20 quarter-final tie.

Yorkshire have also been exploring options with regards to adding a second overseas player to their squad for Twenty20.

"We'll make an announcement about that shortly as to whether we are or whether we're not," said Martyn Moxon, Yorkshire's director of professional cricket. "We've been doing a bit of work on it, but there's nothing definite.

"It's difficult knowing when people will definitely be available."

Yorkshire's Championship game with Glamorgan in North Wales this week will be their eighth of a 16-match campaign. They are currently second in Division Two, 28 points behind Derbyshire having played one less.

The Welshmen are bottom of the table with five defeats and three draws from their eight fixtures.

After this, Yorkshire's next Championship match is against Hampshire at the Rose Bowl on July 11.