Pique's frustration at a failure to make a long-term breakthrough at United could only been exacerbated by the knowledge that the Premier League's other high-profile acquisition from Barcelona's youth ranks, Cesc Fabregas, is now setting the world on fire at Arsenal.
"Because he came through the youth system at Barcelona with Fabregas, who got into the Arsenal team as a much younger age, we had to impress on Gerard his physique was nothing like that of Fabregas," said Ferguson.
"Being a centre-half, he needed time to strengthen and get more experience as a defender. That was what his loan spell at Zaragoza was about.
"Both Gerard and his parents understood that completely.
"In the end, he played 25 games for them and did very well.
"He got more experience, he got tougher and he became a lot stronger. He is coming along the right way."
Ferguson's faith in Pique is so great, he even raised the prospect of the youngster emulating the likes of Paul Scholes, David Beckham and Gary Neville, whose emergence in the mid-90s signalled the end at United for Paul Ince, Mark Hughes and Andrei Kanchelskis.
It wasn't quite a message of warning for Rio Ferdinand, who was rested last night, but the implication of what could happen was fairly clear.
"There is always someone turning a corner in football," said Ferguson.
"Young players break through here. This club is famed for that.
"Sometimes you are forced to make a change simply because you cannot keep these young lads out of the team any longer.
"But waiting is not a problem for a 20-year-old. He will have many opportunities to play when I need to rest defenders and I have the great option of being able to play him in midfield or at right-back."