The 24-year-old defender was shocked to discover that his manager at the Magpies, Ruud Gullit, was prepared to let him go. Newcastle-born, Watson would liked to have ended his career at St James' Park.
"When a club accepts an offer from another club, you know that the writing is on the wall," he said. "I was disappointed and a little surprised. But it's my career and family I have to think about and I'm looking forward to the future."
Now he is relishing the prospect of fighting for his place at Villa Park. "I've got to try to get into a very good side. I'm not expecting it to be easy, but that's what I've got to do."
His new manager at Villa Park, John Gregory, expressed delight with his latest acquisition - and said he was surprised that Gullit allowed Watson to leave. "He's going to be a tremendous addition," Gregory said. "He's got tremendous experience - he played over 200 games for Newcastle and he's only 24 years of age.
"That tells you something about him. I'm somewhat surprised that they were willing to let him go, but I understand the reasons. They need to raise finance and, at pounds 4m, they haven't exactly given him away."
Watson's move to the Midlands will see him link up once again with his long-time friend, Alan Thompson. Both men came through the ranks at Newcastle before Kevin Keegan sold Thompson to Bolton in July 1993, and his former team-mate is delighted to be joining forces for a second time.
"One of the main reasons I'm down here is because I've got friends here, and Thommo's one of them," Watson said.
Wolves are considering a bid to sign the pounds 1m-rated Albanian international striker, Igle Tare. The Molineux club's manager, Mark McGhee, was in Oslo on Wednesday to watch the 25-year-old Fortuna Dusseldorf striker score for his country against Norway in a European Championship qualifier which finished as a 2-2 draw.
Crystal Palace have signed the Torquay United goalkeeper Matthew Gregg in a deal that could eventually be worth pounds 400,000 to the Devon club. The Selhurst Park club have paid an initial fee of around pounds 100,000 for the 19-year-old.
Wigan Athletic have completed the signing of the Barnsley striker Andy Liddell for a fee of pounds 500,000 - less than a fortnight after paying a club record pounds 600,000 for the Coventry forward Simon Haworth.
The Nottingham Forest captain, Steve Chettle, has signed a one-year extension to his current contract. The longest- serving player on the City Ground staff, the centre-half has committed himself to the Premiership strugglers until the end of next season.