The 23-year-old fast bowler was pencilled in to represent Yorkshire during the competition but Cricket Australia have now vetoed that decision.
Stanlake’s representatives and Cricket Australia have decided in a change of tack for the centrally contacted right-armer, who is continuing his recovery from a fractured finger sustained during an IPL stint.
Stanlake was due to play a minimum of 12 matches for the Vikings, possibly missing the opening two through international commitments, but was then due to play right through to final group match against Notts Outlaws at Emerald Headingley (August 17).
Martyn Moxon, Yorkshire's Director of Cricket, said: “Cricket Australia got in touch on Friday and have decided on a different strategy for Billy Stanlake.
“Now the new Australia coach is in place, they want him to play some different cricket to T20 during the period he was due to be with us.
"Consequently, they’ve pulled him out of our deal, which is obviously very disappointing for us. We’re not the only county, it would appear, who has been affected by this."
Moxon added that Yorkshire are unsure of whether to look at alternative replacements or stick with their own players for the T20 campaign, which begins on July 5 at home to Durham Jets.
“We’ll assess the situation as to whether we go for a replacement or not," added Moxon.
"We may choose to stick with our own players.”