Nigel Pearson has warned Watford fans not to expect instant results from 18-year-old forward Joao Pedro.
The Brazilian met manager Pearson and the Hornets' squad on Thursday morning after completing a much-anticipated move from Fluminense which was agreed in October 2018.
He is likely to be introduced at Vicarage Road ahead of Sunday's clash with Manchester United but is unable to make his debut and aid the club in their Premier League relegation battle until next month.
Pearson, who is set to take charge of his first home game since succeeding the sacked Quique Sanchez Flores, is eager to prevent the new recruit being burdened by expectation.
"Hopefully he will have a positive impact," Pearson told the club website.
"It's important for him to settle in and it's important we don't heap too much pressure on a player of such young years.
"We know he is keen to get started and I'm sure he'll get a warm welcome and get support from the players and the club.
"Let's concentrate on the first-team squad who need to go out and find results in the meantime.
"We are pleased to have him here and it's important we don't heap too much pressure on a young player."
Pedro, who has joined the Hornets from the same Rio-based club as former player Richarlison, will undergo a series of medical tests before he is integrated into the squad.
His first appearance could come in the FA Cup third-round tie against Sky Bet League One club Tranmere on January 4.
Bottom club Watford begin the weekend six points from safety after recording just one league win all season.
Former Leicester, Hull and Derby boss Pearson is undergoing a baptism of fire in Hertfordshire, with the visit of Ole Gunnar Solskjaer's United side following a 2-0 defeat at runaway leaders Liverpool.
The 56-year-old is braced for another stiff test of his struggling team's abilities.
"There were lots of aspects that were very, very positive (last week) and we have to build on them," he said.
"We have to convert our chances and that's something everyone in the club is aware of.
"It will be another difficult game.
"They've got quality, players who are capable of being match-winners, but the most important thing for us is to raise our own level of performance, to find a level of consistency that will generate a better feeling within the fanbase."
Adam Masina and Roberto Pereyra should be in contention to feature after minor problems kept them sidelined at Anfield.
Jose Holebas remains unavailable, along with long-term absentees Tom Cleverley, Danny Welbeck, Sebastian Prodl and Daryl Janmaat.
