WELLINGTON: Mitchell Santner, who last played a test in December 2017, returned to the longest format as one of the four frontline spinners in the New Zealand squad for next month's two-match series in Sri Lanka.

The left-arm tweaker is a regular in the shorter forms of the game for the Black Caps - finalists in the last two 50-over World Cups - but was sidelined with a knee problem after playing his 17th test for New Zealand, against West Indies.

He will be joined by left-armer Ajaz Patel, off-spinner Will Somerville and leg-spinner Todd Astle in New Zealand's 15-man squad for the Sri Lanka series, which will mark the beginning of the World Test Championship for both teams.

"Playing three spinners is an option in Sri Lankan conditions and we believe this group provides the best variations and skill mix on offer," New Zealand coach Gary Stead said in a statement.

"England were playing three spinners against Sri Lanka on their successful visit there last year and the slow bowlers also dominated the previous series against South Africa."

England blanked Sri Lanka 3-0 in a three-test series on their visit to the island country last year.

Trent Boult, Tim Southee and Neil Wagner will be the fast bowlers for the Kane Williamson-led side while all-rounder Colin de Grandhomme would also provide an option with his medium pace.

The long-awaited test championship, involving the nine top-ranked test nations competing in a league till April 2021, has been designed to give more meaning to test cricket.

The revamped Future Tours Programme (FTP) will see teams play three home-and-away series over a two-year cycle. The top two teams will then progress to a June 2021 final.

"It's good timing for us after the World Cup," Stead said, referring to their defeat to this month's World Cup final loss to England on boundaries after a tied Super Over amidst heart-stopping drama.

"It was an incredible time for the team and the country, but we're now excited to move forward as a group and sink our teeth into another opportunity."

Squad: Kane Williamson (captain), Todd Astle, Tom Blundell, Trent Boult, Colin de Grandhomme, Tom Latham, Henry Nicholls, Ajaz Patel, Jeet Raval, Will Somerville, Mitchell Santner, Tim Southee, Ross Taylor, Neil Wagner, BJ Watling.