English Premiership side Bath anticipated that the RFU would block their initial attempt to sign All Black flyhalf Stephen Donald and they plan to appeal the decision in the near future.

The decision to prevent Donald from joining Bath, which was made by the RFU and not the Home Office's UK Border Agency (UKBA), was based on the fact that the Waikato pivot had not started for the All Blacks within the last 15 months.

According to the Bath Chronicle the appeal, which must be submitted before August 12, will focus on injuries that Donald suffered in the last 15 months which prevented him from representing New Zealand.

It has also emerged that the rules that led to the RFU verdict were only implemented after Bath had begun discussions with Donald, who has 22 caps for his country.

The regulations came into effect on May 16 when they were signed off by the UKBA. They had been drafted by the RFU Governance Standing Committee, which has representatives from Premiership clubs.

An RFU spokesperson said: "Stephen Donald failed to meet the RFU Governing Body Endorsement criteria to play rugby in England, in accordance with UKBA requirements, because he has not started a game for New Zealand within the past 15 months.

"Bath Rugby are entitled to appeal," he added.

The Bath Chronicle reported that Donald is still keen on the move, and that Bath's appeal is likely to focus on Donald's injury record, as well as his high profile.

The flyhalf required chest surgery in June 2010 and uffered broken vertebrae in March this year. If Bath can persuade the independent appeal panel that such injuries prevented him from playing his way into contention for a starting berth for the All Blacks, then the appeal – according to RFU regulations – would succeed.

An appeal panel would also need to consider "whether the player is able to contribute significantly to the development of the game at the top level in England".

Given that Donald has been understudy to the best flyhalf in the world, Dan Carter, for the past few years, Bath could well argue that he is of sufficient quality to "contribute significantly" to the profile and spectacle of the English game, according to the Chronicle.

The Home Office suggested to the Bath Chronicle this week that the RFU decision had been made to protect the UK labour market.

A UKBA spokesman said: "The responsibility rests with sports governing bodies such as the Rugby Football Union to endorse sponsorship applications from clubs and the application of each sportsperson wishing to enter the UK.

"This is because they are best placed to determine the skill level of a migrant and whether there will be an adverse impact on the resident labour market of their sport," he said.

The Chronicle reported that Donald had agreed terms and signed a contract with Bath following the expiration of his deal with Hamilton-based Super Rugby side the Chiefs.

It is also understood that the senior management at Bath, who have not commented on any reports linking Donald to the club, had been aware that he needed both RFU endorsement and then migration clearance from the UKBA.

Donald has made three appearances for the All Blacks in the past 15 months, but all from off the bench. Last month - after he had been linked to Bath - he was dropped from the New Zealand squad ahead of the World Cup

Sophie Barrett-Brown, a leading immigration expert with international sports law specialists Laura Devine, told the Chronicle that Bath had no option but to request an appeal if the club wanted to persist in its bid for Donald.

If the appeal fails, then it could demand a judicial review but that could have huge financial ramifications.

"There has to be the governing body's endorsement, there is no way around that," said Barrett-Brown.

"Judicial review is the only potential way around it but that is costly and risky. If you are unsuccessful the costs of the other party can be awarded against you," she added.

Should Bath call for a review, then the panel would comprise an independent chairman, an RFU representative and a Premiership Rugby representative.