Ireland coach Phil Simmons yesterday gave the simplest of explanations as to why Craig Young has not bowled a ball in the World Cup so far - other bowlers have been bowling better.

He gave no clue that the Bready opening bowler will make his debut against Zimbabwe here tomorrow (3.30am live on Sky Sports World Cup) in Ireland's must-win fourth group game.

But after Max Sorensen conceded 21 runs in his first two overs against South Africa on Tuesday and finished with six overs, no wickets for 76, there is sure to be one bowling place up for grabs.

The four players who were not involved in the 201 runs defeat to the Proteas in Canberra were the only squad members at Ireland's net session in Hobart with Alex Cusack and Young in effect bowling off for a place in tomorrow's starting 11.

There was no indication that Peter Chase or Stuart Thompson will be considered.

Young's absence, though, has been the major talking point after his consistently impressive bowling throughout the winter, right up to the warm-up game against Scotland in Sydney last month.

But the first clue to the thinking of Simmons and captain William Porterfield for the World Cup opener came in the last warm-up game, against Bangladesh on February 12, when John Mooney and Sorensen were given the new ball, Young came on second change and his solitary over went for 13. He hasn't bowled a ball in anger since.

Simmons has finally confirmed it wasn't that over which cost him his place in the World Cup side.

"That one over wasn't the reason. We pick from 15 every match and we see what's happening in the nets and in the field and make a choice as to who is looking sharpest and what's best for that game and it will be the same again in Saturday's selection," Simmons said.

"Rather than say Craig hasn't looked good in the nets I'd rather say he's done well but others have done better. That's the better way to look at it.

"But it's not just the nets, it's what we come up against and going into the first game (against West Indies) Max was bowling well, the best of the seamers actually, and we've been lucky we've had 15 to choose from every match," said the West Indian.

The bowlers must get it right tomorrow because Simmons admits the dent in the team's run-rate following their heavy defeat by South Africa leaves Ireland realistically needing victory to keep alive their chance of a quarter-final place.

Defeat will not end their hopes but then even victory in their last match against Pakistan on March 15 - assuming they don't pull off the mother of all upsets against World champions India next Tuesday - may not be enough to reach the knock-out stages.

"We don't think about losing, we think about winning every game, but Zimbabwe have played well so far and we know we need to win to move forward on the 16th," added Simmons.

"We have to put everything into that and hope everything goes our way. The run rates are there and we have to win to make sure we are in the mix."

One player certain to keep his place is Donemana slow bowler Andy McBrine who, Simmons added, "has been the best of all the bowlers so far on tour".

Despite Zimbabwe winning only one of their last 10 ODIs, Ireland will have to be at their best because the Africans have been competitive in most of them, including defeat to South Africa by only 63 runs.