McKee's next race could be the NI Championships on 12 June

McKee competed in a British League meeting last Saturday but he has been unable to train since then.

"It's been bothering me for several weeks and I've now been told to rest completely," said McKee.

McKee is unlikely to compete again until the Northern Ireland Championships on 12 June.

He had planned to start his season in earnest in Hungary on the final weekend of this month but that is now a non-starter.

In addition, McKee has ruled himself out of meetings in Poland (5 June) and Zaragoza (8 June) when Ireland's 4x400m squad will be chasing Olympic qualification.

McKee's latest problem will be a blow to Ireland's hopes of earning qualification for the relay event.

Despite his struggles for fitness, McKee is remaining upbeat about his chances of qualifying for the Olympics.

"I aim to have at least two attempts at the 400m standard before the Olympic Council of Ireland's deadline of 3 July.

Paul Brizzel has recovered from an Achilles problem

"One of them is likely to be in Namur in Belgium on 2 July which could be a good chance as it is quite a fast track.

"I know I'm going to be running well come July and given that the international deadline is several weeks more than 3 July, hopefully the OCI would show understanding for athletes who are rounding into form in July and getting the times."

The Olympic standard of 45.55 is .03 faster than McKee's Irish record set in 2002.

McKee's compatriot, Paul Brizzel, meanwhile, plans to decide on his racing programme in advance of Athens after meeting his coach Mike McFarlane next week.

Brizzel, who has already qualified for the games, needed treatment for an Achilles problem after the World Indoor Championships in March but now says he's in "good shape".

"We haven't worked out a schedule yet but the thinking is that I'll probably run a few 100s in the early part of the season," said Brizzel.

Meanwhile, Dermot Donnelly made a solid start to his season by finishing third in 8:07.04 behind Rob Connolly (8:03.34) and Mark Christie (8:04.47) at a meeting in Dublin on Wednesday.