Tim Murtagh arrived in Dubai early this morning as cover for Alex Cusack as Ireland's injury woes at the World Twenty20 Qualifiers intensified.

Already without one all-rounder, John Mooney, who tore his hamstring during the Scotland match on Sunday, the Ireland management team are so concerned about Cusack, who left the field after bowling just two overs in the same match, that they summonsed the Middlesex pace bowler to join the squad for the sudden-death play-off games, over the next three days, which will decide which two teams go through to the finals in Sri Lanka in September.

Cusack is receiving treatment for a tight hamstring and, with the emergency call for Murtagh, his participation in the rest of the tournament is, obviously, a major doubt. His fitness will be assessed ahead of tomorrow morning's game against Canada in the Dubai International Stadium in the first of three Ireland games, all of which must be won, if they are to go through to the finals.

It is Murtagh's first involvement with the Ireland squad – the 30 year old Englishman is an Irish passport holder but qualified to play for his adopted country only last month – but he is good friends with Ed Joyce and Gary Wilson, the former from his Middlesex days, and he is also a team-mate of Paul Stirling at Lord's.

He has been on the Middlesex staff since 2007, after six seasons with Surrey, and in Twenty cricket he has taken 80 wickets at 26.55 and has a highest score of 40 not out, although an average of less than 10.

Murtagh was favourite to be called up when Mooney was forced out of the tournament on Sunday night but the selectors surprised everyone by calling up Andrew Poynter, the Clontarf batsman, because, in the words of National Coach Phil Simmons, "we still have seven-eight bowlers but we will need batting cover if Cusack fails to make it". Now with Cusack unlikely to play any further part in the tournament, they call up Murtagh! There must be logic there somewhere.

Watching all this from within the original squad of 14, with increasing frustration and, probably, anger is Instonians opening batsman and wicket-keeper Rory McCann who continues to be overlooked.

It came to a head yesterday when Poynter was selected for Ireland's final group game against Oman, despite arriving in the UAE only nine hours earlier and not having played cricket for six months, while McCann whom, it could be argued, is at least as good a batsman as Poynter, has been travelling and practising with the Ireland squad for the last six weeks and played all three ODIs in Kenya.

Ireland were already certain to make one change from the team that beat Oman yesterday by 44 runs, their sixth successive win but only good enough for second place in Group B behind Namibia, with the rested Trent Johnston returning for Poynter. Now the selectors have the county experience of Murtagh at their disposal and Max Sorensen or, as usual, Andrew White, could be at risk