Worcestershire have replaced Colin Munro with fellow New Zealand international Mitchell Santner for this summer's T20 Blast.
The 23-year-old left-handed all-rounder is due to link up with last season's quarter-finalists in mid-May.
Santner, who made his international breakthrough in limited-over cricket on last summer's tour of England, made his Test debut in November.
He scored 31 and 45 and took two wickets against Australia in Adelaide.
"It has been a breakthrough time for me in terms of New Zealand," said Santner, who will join fellow Kiwi Matt Henry for the first part of the county's T20 programme.
Following the tour to Australia, the slow left-arm spinner kept his place for a two-Test series against Sri Lanka, adding a further four scalps.
"To have an overseas player with three strings to his bow will be a huge bonus to our T20 Blast ambitions," said director of cricket Steve Rhodes, who is currently away as assistant coach with the England Lions squad for the one-day series against Pakistan A in Dubai.
"He presently plays all formats for New Zealand and bats in the top six. He is a genuine left-arm spinner so he will give our bowling terrific balance and his athletic fielding will add to an already good fielding squad."