Harris, promoted to start at stand-off in the Test at Bolton on Saturday that saw the Kiwis clinch the series, strained a groin and is regarded as very doubtful for Watford this Saturday. His absence could give St Helens' Sean Long a chance to make his mark on the series.
Despite advance claims that he was fit to play at Bolton, Britain are still likely to be without Adrian Morley, while Paul Newlove is also far from being a certain starter.
And, according to the Kiwis' stand-off, Robbie Paul, Britain can forget about the possibility of them going easy now that the series is won. "We want to win the series three-nil and be remembered as the best Kiwi side of all time," he said. The New Zealand coach, Frank Endacott, has indicated that he might use some of the fringe players who have not been involved in the series so far.
"But there are some very good young players with us and we would not lose anything by bringing them in," he said.
His British counterpart, Andy Goodway, has been reassured that his job is not in danger, despite the scale of the defeat at Bolton, when his side let in 28 points without reply in the second half.
"Good coaches don't become bad coaches because of one Test series defeat," said the Rugby League's chief executive, Neil Tunnicliffe. "They have to be given time to grow into the job."
Goodway has a contract taking him to 2001 and an administration that has stressed the value of continuity is not likely to make any knee-jerk reaction.