Rutherford had initially signed to play all formats this summer, but will only play in the Blast after the postponement of so much of the county season. The ECB will announce which formats will be played next week, but it is anticipated that the T20 Blast will start in September and run into early October.
"It's been a bitterly frustrating time for anyone in cricket all around the world and it's no different for Hamish," said Alex Gidman, Worcestershire's head coach.
"We are looking forward to him coming back. Hamish and Riki Wessels can cause quite a lot of destruction at the top of the order and it's important for us as a club and as a group of players that we challenge as much as we can in that competition.
"It's something we've been successful in for the past two years and, regardless of how that competition looks this year, we want to try and do as well as possible in it."
Rutherford, the New Zealand opening batsman, is set to be one of only a handful of overseas players in the Blast this season, with most signings cancelled in order to cut costs or due to clashes with revised international fixtures or the start of the Australian domestic season. Northants remain hopeful that Paul Stirling will be available to play for them, while Birmingham Bears are optimistic about their chances of getting Chris Green over, since he does not have a state contract.
Paul Pridgeon, the chair of Worcestershire's cricket steering group, confirmed that Turner's deal with the county was off. "Because of the change from the original T20 dates, Ashton would not be available for the entire competition because he would be required to return for practice by his state side," he said.