The soul searching has begun again in earnest at Rangers after another dreadful display against arch-rivals Celtic this season. In five matches they've failed to win any and have lost four, being dumped out of two cup competitions at the semi-final stage in the process.

Perhaps most disappointing on Sunday was the lack of fight in Pedro Caixinha's side. Fans expect what's absent in quality to be made up by passion and determination at least. None of it was on show.

Celtic breezed past last season's Scottish Championship winners, in the first half barely letting the Light Blues have possession of the ball.

A massive summer rebuild is required and it's quite the task on a limited budget. Last season saw arrivals like Joey Barton, Joe Garner and Philippe Senderos all fail to make the grade.

This upcoming transfer window needs to be much more successful or it will be another season of pain.

Here are FOUR stars we reckon would cheer Gers fans up if the club could swing deals for them...

Graham Dorrans

Graham Dorrans is a boyhood Rangers fan who, after successful spells in England, could return North of the border to be a leader on the park in the Scottish Premiership. The Norwich midfielder is still just 29 and has plenty to offer at a high standard.

Having failed to become as important for Norwich as he was for West Brom, he's said by The Scottish Sun to be available this summer.

It would be quite the coup for Rangers to land him. But far from it being a pointless headline grabbing exercise in the vein of Joey Barton, Dorrans could well be the answer to supporters' midfield prayers.

His eye-catching performances for Livingston many years ago of course attracted West Brom to him in the first place and he knows how to get the job done in Scotland. In an area of the pitch the Gers were particularly lacking in on Sunday, could he be a difference maker next season?

Kyle Lafferty

Coincidentally another Norwich man who Rangers should swoop for this summer is Kyle Lafferty.

Having left the club in 2012 in the wake of the financial meltdown, he went on to enjoy a decent spell at Palermo in Italy before signing on at the Canaries. His time in Norwich has been less than successful but he's certainly a player with a proven track record at Ibrox, having won multiple trophies with the club.

The 29 year old is of course an international star too and regularly turns out for Northern Ireland, banging in 20 goals in 58 caps.

That's not a record to trifle with and given Kenny Miller is ageing and the likes of Martyn Waghorn and Joe Garner are rapidly running out of steam at Ibrox, a move for the attacker could make perfect sense.

Callum Paterson

Callum Paterson is currently in the midst of rehabilitation from a long-term injury but is still reckoned to be one of the brightest prospects in the Scottish top-flight. His physical attributes and desire to impact games has made him a stand-out at right-back, even winning international caps with Scotland while at Hearts.

His contract at Tynecastle is up at the end of the season and he's planning an exit. Where that'll be remains to be seen but he would fit in perfectly at Ibrox and provide serious competition for James Tavernier, whose defensive positioning has been incredibly suspect this season.

Signing him up would show ambition and be a real coup for the club, with Paterson likely to attract attention from lots of clubs when he returns to full fitness.

Is he the man to add defensive stability to Rangers' right flank?

Louis Moult

A more prolific goalscorer than anyone at Ibrox this season, Louis Moult could be the answer to Rangers' lack of firepower this season. The Motherwell man has scored 16 goals this season in a struggling 'Well side and appears to have what it takes to step up and deliver for a higher quality team.

At just 24 years of age he has plenty of room to improve and we've seen from the likes of Scott McDonald in the past that poachers at the Steelmen can make the transition to life at the big Glasgow clubs.

Martyn Waghorn and Joe Garner have been found lacking this season despite having a reputation of goalscoring and it's clear that Pedro Caixinha needs a different option. Shopping in Scotland could prove to be cheaper than heading abroad and a move for Moult could be the missing piece of the attacking puzzle at Ibrox.