Expectations were high when both players arrived in the summer with hefty price tags - Lafferty cost more than £3million from Burnley, while United States international Edu arrived in a £2.6million deal from Major League Soccer.

But neither has made a major impact so far or featured in the first team as much as would have been expected.

However, Smith is confident both players will eventually make their mark at Ibrox.

"I felt we had to bring in a few younger players and it always takes a little bit of time for them to settle in," he said.

"Lafferty and Edu will play a big part for Rangers in the coming years, I've no doubt about that.

"But it does take them a little time to settle and at Rangers you have to have experienced players around you as well.

"Even the younger ones who have played in Scotland for quite a number of seasons, your Steven Whittakers and Kevin Thomsons, took a bit of time to settle into the team.

"Nowadays we are not able to get a higher level of player.

"We were able to go to England and get them in previous times, but now we have to look at the younger ones.

"And people's expectations of the younger ones should not be the same as those on the experienced players."

Veteran defender David Weir settled quickly into life at Rangers when he arrived from Everton two years ago.

But he has sympathy for younger, less experienced players who arrive at a club where demands are high.

"When you are at a club like Rangers you just have to get on with it," he said.

"It's a hard place to play and learn, but the benefits here far outweigh the negatives.

"There are not many clubs in Britain or indeed the world where the expectations are for you to win every week.

"You are expected to win well and play well and for young lads and guys who are not used to it then it's a big ask.

"It can be a harsh place to be because if you don't win it's an immediate crisis.

"I'd always rather be here, though, than at some club where it didn't really matter."

Rangers head into tomorrow's clash at Inverness trailing leaders Celtic by seven points in the Clydesdale Bank Premier League following last week's Old Firm derby defeat.

Weir added: "You never feel there is a margin for error - if you feel that then you are at the wrong place.

"We should always look to win the next game. If you think you can drop the odd point here and there then it's the wrong attitude."