McGowan only played against Halifax because his coach, Peter Fox, had allowed the first-choice winger, Gerald Cordle, to go home to Wales for Christmas.
He scored a hat-trick, but also suffered a 'dead' leg which threatens to keep him out of today's semi- final against Castleford at Odsal.
Cordle will return on the right wing, but McGowan is bracketed with Brimah Kebbie for the left. Paul Medley, who has played hooker and wing in recent weeks, drops to substitute.
Castleford lost at home to Bradford in the league four weeks ago - a match in which their coach, John Joyner, knows they made enough chances to win. Richie Blackmore, who would have been an antidote to the power of Bradford's Paul Newlove in the centres, is still out, with Tony Smith continuing to deputise.
There will be little to choose between two sides who combine physical strength and enterprise today, but home advantage and heavy conditions could favour Bradford, beaten in last year's final by Wigan, who meet Salford in the second semi-final next week.
Tomorrow brings two highly significant First Division games. If Wigan can repeat their convincing Regal Trophy victory over Warrington, they will go ahead of them on points difference with two matches in hand and will look the most solid of bets to retain their championship.
Their depth is emphasised again by the return of Denis Betts as a substitute, but Shaun Edwards is out with a shoulder injury.
Warrington hope to have John Thursfield and David Elliott fit in their pack, but would be wise to find a place for the experience and inspirational qualities of Mike Gregory.
Eric Hughes takes charge of St Helens for the first time against his old club, Widnes. He is without Bernard Dwyer, as well as the long- term casualties, George Mann, Tea Ropati and Alan Hunte, so the reserve hooker, Tommy Hodgkinson, makes his full debut.
Oldham's prop, Tiny Solomona, currently out with a broken arm, is joining the exodus of British-based players to the Auckland Warriors.Reuse content