The Blast's schedule has been compromised by the combination of June's T20 World Cup and the Hundred's summer-holiday window this season, and there is a six-week gap between the end of the group stages and the quarter-finals this season. It has left several counties scrambling to find overseas players who will be available in mid-September.

Lancashire will circumvent that rule by adding Dockrell to their squad for their final two group games at Emirates Old Trafford, against Nottinghamshire on Wednesday night and Northamptonshire on Friday. They have not yet mathematically qualified for the quarter-finals but another point would secure their progress.

"We are really pleased to add George into our squad for the rest of the Vitality Blast this year," Dale Benkenstein, Lancashire's coach, said. "With the potential for knock-out round matches in September and uncertainty around player availability, George provides us with another overseas option for the latter stages.

"He will go straight into the squad for the final two matches of the group stage this week [and] will offer us an experienced left-arm spin option, while he can also be a match-winner with the bat in the finisher role as he has proven on the international stage with Ireland."

Green, the Australian offspinner, is Lancashire's leading wicket-taker in the Blast this season with 13 but his contract initially only covered the group stages, and he is due to play for Antigua and Barbuda Falcons in the CPL from August 29 until October 6. He could feasibly be available for Finals Day on September 14 if he flies back to the UK between games.

Dockrell, who has reinvented himself as a batting allrounder after spending most of his career as a specialist left-arm spinner, said he was "delighted" to join Lancashire. "We are in a really strong position in the North Group, with two important home games remaining as we look to secure that all important home quarter-final at Emirates Old Trafford in September," he said.