Rangers would send Celtic a clear message that they are ready to compete for the Scottish Premiership title if they are able to persuade Joey Barton to sign, according to Ronald de Boer.
The former Netherlands international, who played at Ibrox between 2000 and 2004, has been impressed by the club's pursuit of the experienced midfielder after sealing their return to the top-flight for next season.
Barton - Burnley's Player of the Year in their own successful promotion campaign this season - was shown around Rangers' training ground last week and has reportedly been offered a three-year deal.
De Boer is hopeful a deal can be concluded as he feels Barton, 33, would be an ideal acquisition to help Rangers' emerging youngsters under manager Mark Warburton.
"If he comes I think it will be a good signing," he told Sky Sports.
"He has the knowledge of the game, he has seen everything. It sends out the message that they really want to challenge for the title.
"Everyone knows the magnitude of Rangers in Scotland, they know they will be the biggest rivals for Celtic but they have to strengthen in some places.
"It is also important because Rangers are nowadays a young team and they need a guy with experience, not only on the pitch but on the training ground and in the dressing room because next year it is really going to matter.
"Being back after so many years, you want to have a great start so you need a leader and I think Joey Barton can do that."
Rangers will seal a Europa League spot if they beat Hibernian in Saturday's Scottish Cup final at Hampden, which De Boer thinks will be crucial to their pulling power.
He said: "If you want to sign people, that [European football] is very important. It will attract players. Rangers is a huge club and they are now back."