Robert Taylor, the striker bombed out by City in the summer, could come back to haunt them at Valley Parade.
The well-travelled frontman failed to impress in a week's trial with the Bantams last month. He was released after being taken off at half-time in a friendly with Hartlepool.
Now he is ready to line up against City after re-joining visitors Grimsby on a short-term contract.
Taylor, who spent a loan spell at Blundell Park last season, has signed a four-month deal as cover for fractured skull victim Steve Livingstone.
He played 45 minutes in a reserve game on Wednesday night and boss Paul Groves will throw him straight into first-team action for a clash which, even at this early stage of the season, is seen as crucial.
If Taylor needs any more incentive, he was also sent off when the clubs last met in February for lashing out at on-loan defender Stephen Caldwell.
City boss Nicky Law said: "We were doing Bob a favour by giving him some matches and getting him fit.
"I wasn't in the position then to make any signings and if I'm brutally honest I probably wanted a different type of player, slightly younger and more mobile who could put defences under pressure.
"It's Sod's Law that Bob will come here, play well against us and do something silly like score."
Law must do a deal today if he is going to bring in the loan striker he has been chasing.
He has spoken to a Premiership club and said: "We're looking to clubs with a good heart who are willing to contribute some of the salary.
"I've got a set figure I can use on loans and a couple of decent players would wipe that out."
Paul Evans is back in training after his appearance for Wales in Croatia where he came on as a late substitute.
He was hoping to be named in the squad announced today for the opening Euro 2004 qualifier in Finland on September 7.
It would rule him out of City's home game against Coventry.
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