Yorkshire first-team coach Jason Gillespie has explained why Moin Ashraf has been absent from LV= County Championship cricket this season.

Out of the eight senior fast bowlers at Gillespie's disposal, only Ashraf and Iain Wardlaw have not been handed an early four-day opportunity as part of the Australian's rest and rotation policy.

Ashraf played the last eight Championship matches of 2012, taking five wickets in the promotion clinching win against Essex at Chelmsford last September.

Before the start of the season, his primary goal was to force his way into the Championship team on a regular basis.

"I know it's going to be difficult with the quality of bowlers we've got in the squad. We've got so much talent. But I'm ready for the challenge. That's my aim this year, to get into the Championship team and do well," he said in early March.

But the 21-year-old has had to settle for two appearances in 40-over cricket this summer, in which he has taken only one wicket.

He would have played in Sunday's win over the Unicorns had he not been struck down by a migraine before the toss.

"I had a good chat to Moin on the way down to Edgbaston (last week)," said Gillespie. "Obviously he didn't perform in the first two one-day games as much as we'd like. His pace was down and his skills, he just wasn't getting right.

"I had a good, long, honest chat with him. We knew that if he wasn't going to play against Warwickshire, he had a lot of work to do. He did a lot of fitness work and bowling - just refining his skills.

"A couple of minor technical things crept into his game, which we felt we needed to address. He worked his absolute butt off last week. He was hitting my glove hard, and I always know when he's bowling well because it's hurting my finger when I take it in the glove."

Ashraf is the youngest quick in Yorkshire's first-team squad, and he was picked out by a number of pundits as one to watch this summer following his exploits in last season's Twenty20 competition.

But, with the arrival of Jack Brooks and Liam Plunkett, it was no great surprise to see him miss out at the start of the Championship campaign.

"We've got absolute faith in Mo," added Gillespie. "At the moment, he's not playing in the four-day stuff, but that doesn't mean he isn't going to. We've been very clear on that with him.

"He just can't force his way in at the moment because the other bowlers are bowling well. In the one-dayers, however, we can continue to give him opportunities."

Meanwhile, Gillespie has revealed the moment he knew he would have to strengthen Yorkshire's bowling stocks for this season.

"Where it hit home for me was when we played Gloucestershire at Scarborough (last August)," he said. "Ryan Sidebottom pulled up stiff on the morning of the game with his back, and we were short.

"A couple of the second-team bowlers weren't bowling well. We made the decision to have Anthony McGrath as third seamer with Moin and Steve Patterson as our frontline seamers.

"Coming into Division One, if we were going to challenge, we needed more depth because things happen with injuries and selection."