The Northern Ireland international Lafferty was signed for £3M from Burnley on Monday, but Sanchez said it was a lot of money for a young lad.

"He's not the finished product," said Sanchez.

"People should not expect too much of him in his first season.

"He needs time to develop. He's still learning the game and he'll need time to make the step up but I've no doubt he'll make it."

Lafferty, 20, has agreed a £3m switch to Rangers from Burnley, with Alan Gow poised to go the other way.

"I tried to sign him when I was at Fulham but was quoted £6m and the finances got out of hand," added Sanchez, who gave Lafferty his first taste of international football.

"But if he develops the way I think he can - if he listens and learns and takes on board the things that people like Ally McCoist are telling him - then, in a year or two, £3m will look very cheap."

Kyle has scored 10 goals in 56 appearances at Turf Moor and five goals in 16 internationals.

"He did tremendously well for me," said Sanchez.

"David Healy obviously got the plaudits for scoring all the goals, but without Kyle's hard work alongside him I don't think he would have had the number of opportunities that came his way.

"He has spent a lot of his time at Burnley playing wide on either of the wings and he's developed in that position.

"I think he's an out-and-out centre forward but he got valuable experience out wide and did a good job.

"He's about 6ft, 4in and very much in the mould of Peter Crouch."

Sanchez added: "He's a lot better on the ground than you'd think because of his height but he could probably improve his heading a little bit.

"He's not quite as good in air as you would hope for someone that big. But he's a young lad who can only improve."

Lafferty was a Rangers supporter as a boy and Sanchez believes the forward will be thrilled by the move to Ibrox.

"I'm sure he's very pleased," he said.

"But until you're actually there, playing in front of 60,000 people, you don't realise what it's all about.

"It would be nice if he could link up with Steven Davis, another young lad I blooded at international level, who I understand did a fantastic job on loan at Ibrox last season."