ENGLAND are delaying making a decision about their line-up for the third Ashes Test until tomorrow morning to give fast bowler Andrew Caddick an extended opportunity to prove his fitness.

The Somerset fast bowler has been a doubt ever since contracting a back spasm during the latter stages of England's innings-and-51-runs defeat during the second Test at Adelaide, which prevented him bowling after tea on the third day and forced him to bat at number 11.

He has since had a steroid injection into his back in an attempt to speed up his recovery and a pain-killing jab yesterday which allowed him to bowl almost normally during the net practice at the WACA this morning.

But perhaps anxious that Caddick may suffer a recurrence of the complaint and pull up in the middle of a Test they must not lose if they are to retain an interest in the series, England are remaining cautious about naming him in their line-up until he has been given a series of fitness tests.

"Caddick is still going through a bit of a trial and will be coming down to bowl this afternoon and we want to see how he reacts to that," explained coach Duncan Fletcher today.

"It's encouraging by what we saw of him this morning, but that can be misleading and that's a decision we have to make - we have to make sure there aren't any niggles arising as he cools down.

"We may even want to see him have another bowl in the morning before the Test before we make our decision."