Last updated on .From the section Football

Rangers manager Pedro Caixinha's ability to overhaul his squad will be limited by the contracts some of his players are on, fears Kris Boyd.

The Kilmarnock striker, a prolific scorer in two spells at Ibrox, feels his former team are "a million miles away" from challenging Celtic.

"Is there anybody going to buy any of these players?" said Boyd.

"These guys are probably on the most they will ever earn in their careers so they are not going to leave."

Caixinha, who replaced Mark Warburton as Rangers manager, has been in charge at Ibrox for seven matches.

His team are 36 points adrift of treble-chasing Celtic in the Premiership, and nine behind second-placed Aberdeen.

Rangers were hammered 5-1 by Celtic on Saturday, the biggest defeat they have suffered at the hands of their rivals at Ibrox.

It follows Celtic's 2-0 win in the Scottish Cup semi-final the previous weekend.

Rangers have won three, drawn two and lost two - both to Celtic - in Pedro Caixinha's short period in charge

"As a new manager coming in, he will have an opportunity to sign players," Boyd told BBC Scotland.

"Every manager will have a shopping list but where is the money coming from to turn it round?

"You've still got a squad of 20 players and I can't think of any of them, apart from Clint Hill and Philippe Senderos being out of contract in the summer.

"You'd have to get rid of them one way or another, but the wage bill can't jump away back up. It's about balancing everything.

"The big problem is that when you tell people they are not needed, they will just down tools.

"When they are told they are not needed, you have to find money to pay these guys off. They become a hindrance hanging about the place."

'The gap is getting wider'

Boyd, 33, acknowledges it is very days for Caixinha, but says he has yet to see Rangers develop under the Portuguese.

He said: "The gap is getting even wider. When you do something mid-season you usually get a reaction from the players. I haven't seen any.

"I know there's not been a transfer window but you can always judge what a manager gets out of players in that short period of time.

"Rangers were a far better team earlier in the season. They weren't taking chances but they were dominating games.

"They were difficult games to play against Rangers whereas now it's just like playing against anyone else. The fear factor is not there.

"Scottish football needs a strong Rangers, even for the national team because they can make players better for the country.

"You just want to have a team out there who can challenge Celtic at least. But it's a million miles away."