Marnus Labuschagne and Michael Neser will miss the early stages of the County Championship season following the extension of the Sheffield Shield season, with Glamorgan recruiting Ireland captain Andy Balbirnie as a short-term replacement for the opening weeks of the campaign.

The Shield season is set for its latest-ever finish, with the final due to be played from April 15-19, and with Queensland second in the table with two rounds of games remaining, there is every chance that Labuschagne and Neser will be involved in that fixture.

As a result, Glamorgan are looking for replacements for both of their overseas players, and announced the signing of Balbirnie on Wednesday for up to six weeks as a stand-in for Labuschagne. Balbirnie was the club's leading run-scorer in the T20 Blast last season, and described the move as a "brilliant opportunity" having previously voiced his frustrations about the scarcity of Ireland's red-ball fixtures since they were awarded Test status.

Ireland have not played a Test since July 2019, when they gave England a scare at Lord's, and reports in their local media have suggested that their fixture against Sri Lanka later this year will again been postponed. There will not be a single first-class game in the domestic season either, after Cricket Ireland opted to prioritise white-ball cricket in light of the international schedule.

The season opener against Yorkshire on April 8 will be Balbirnie's second appearance in the County Championship. He spent several years on Middlesex's books, but was limited to a solitary Championship game, against Surrey in 2012.

"The County Championship is historically one of the best first-class competitions in the world," he said. "I really enjoyed my time in Wales last season - the players and coaches were incredibly welcoming and it's a great place to play. I'm really excited to go back, get stuck in and hopefully contribute to some wins for Glamorgan."

Mark Wallace, the director of cricket, said it was "disappointing" to be without Labuschagne and Neser for the early stages of the season.

"We're very happy to get someone the calibre of Balbo in on such short notice," he added. "As he showed last year, he's a fine player and has a good track record across all formats and experience playing at the very highest level. He was fantastic for us when he joined last year and will bring plenty of skill and leadership to our side."

Balbirnie will return to Ireland in May to play in the inter-provincial season, before leading the ODI side in their World Cup Super League series in the Netherlands in June. He was one of three Irish overseas players to impress in last year's T20 Blast, alongside Paul Stirling and Gareth Delany, but this year's international schedule means their availability for the competition will be limited.

Richard Holdsworth, Cricket Ireland's performance director, said: "We have a big year ahead of us at both international and domestic levels, with a T20 World Cup in late 2021, so for one of our key players to be able to take advantage of an opportunity to play cricket in April at this standard will be of great benefit."