Manchester United insist keeper Tomasz Kuszczak's has signed a four-year deal with them, despite the first season being spent on loan from West Brom.
Kuszczak's immediate future has finally been settled
Paul McShane and Luke Steele went the other way as part of the deal.
"He has come to us on loan for the first year and then will join us permanently in July 2007," said United chief executive David Gill.
"We would not have been interested in signing any player, even as one as good as Tomasz, on loan."
He added: "We would hope Tomasz remains a Manchester United player for many years to come."
Kuszczak, 24, will act as understudy to Edwin Van der Sar, with youngster Ben Foster staying a second season at Watford.
"He has plenty of ability and knows what challenges the Premiership presents," said United manager Sir Alex Ferguson of the 24-year-old.
"He will benefit from working alongside a great keeper like Edwin van der Sar."
Kuszczak expressed a very strong desire to join United
West Brom boss Bryan Robson
Van der Sar is expected to retire after Euro 2008, at which point Kuszczak will press for a first-team place.
West Brom boss Bryan Robson admitted that he was reluctant to allow Kuszczak to leave the Hawthorns.
"I have had several meetings with the player," Robson told the West Brom website.
"He expressed a very strong desire to join United, with the potential of playing in the Premiership and Champions League.
"In the end, we felt that these were exceptional circumstances and that we would be denying Tomasz a major career opportunity if we insisted on him staying."
Kuszczak, who has won four caps for Poland, spent three years in Germany with Hertha Berlin before arriving at West Brom two years ago.
Sir Alex Ferguson's attempts to land the keeper had been frustrated throughout the summer, with an initial £2.5m bid rejected.
But with Kuszczak now at Old Trafford, Foster getting Premiership experience with Watford and Tim Howard on loan at Everton, United are hopeful they have enough strength in the goalkeeping department to maintain healthy competition for the next five years at least.
The transfer of Steele is unlikely to go down well with Coventry, who signed the youngster on loan from United.
But the player was recalled, then immediately sold to one of their local Championship rivals.