Although his namesake, the Bradford coach, Peter Fox, has been mysteriously reticent on the subject this week, Deryck has known since Wednesday that he will be in the starting line-up at Elland Road. He believes that the groin injury which has blighted the second half of his season has now healed sufficiently for him to go into the game with confidence.
'It feels a lot better than it did when I came back for the Regal Trophy final,' he said. That match in January, also against Wigan, saw Fox lacking in mobility and unable to kick in general play as Bradford put up a fight before losing 15-8.
This time, after a series of cautious run-outs, he can move freely. The only thing he has been told to avoid is taking goal kicks, as that puts strain on different muscles from kicking out of the hands.
Fox's presence means that David Watson will play full-back, with Roger Simpson moving to the wing in place of Mike Taylor. Neil Summers returns at stand-off and Paul Medley, playing some of the best rugby of his career since moving to loose forward, is preferred to David Heron.
Both Foxes believe that the Wigan coach, John Monie, was foxing last week when a team lacking a number of regulars lost 23-16 to Bradford in a league match. That sounds rather far-fetched, as Wigan are hardly likely to damage their prospects in one competition for some notional advantage in another. What is probably the case is that the result is as irrelevant as Bradford's 71-10 defeat by Wigan in last year's semi-final.
'The Regal Trophy is a much better guide to form,' Deryck Fox said. 'If we can keep our defence sharp, it will be a very close game again and then anything can happen.'
The keynote of Wigan's season so far has not been that they cannot be beaten; it has been the efficiency with which they can recover from setbacks. They have shown several times that they are capable of falling well short of their usual standards in particular matches - dropping passes and missing tackles. With only Billy McGinty missing from their full-strength side, Dean Bell will captain the team from loose forward, with Joe Lydon in the centres.
Wigan's defeat at Odsal last week could benefit them more than it will Bradford. 'It has put an important element of doubt into our minds,' Wigan's Australian centre, Andrew Farrar, said. 'We know now that we have to have the greatest respect for them.'
Tomorrow could be a significant day for Wigan in the First Division. The one side that could deny them a fourth consecutive championship, St Helens, are at Warrington and run the risk of a defeat that would virtually end their ambitions.Reuse content