The Ibrox outfit have received a lot of attention in recent days as a result of Joey Barton.
The 33-year-old midfielder, who joined the Gers on a free transfer from Burnley this summer, has made headlines over the last few days after suggesting that the Celtic skipper is not in the same league as him as a footballer.
The outspoken Barton is certainly turning Celtic fans against him before he has even kicked a ball for Rangers, and Johnstone feels that such comments are not going to please manager Warburton.
"The club should be having words with players to make sure that they aren’t coming out with personal slurs on other professionals, because all he has done is stir it up," he told The Glasgow Evening Times.
"That’s what social media is all about, I know that, but I don’t think that helps the club. Use it for certain things, sure, but Joey isn’t even here yet and he’s upsetting an awful lot of people.
"It might be great for him getting more followers on Twitter, but from a footballing perspective I can’t imagine Mark Warburton being too happy about it."
While Johnstone might have a point, the Rangers boss will have known all about Barton's colorful personality when he signed him.
If he can walk the walk after talking the talk then Warburton might not be upset in the long term.
But the fact is that the former Newcastle United midfielder is drawing a lot of attention to the Ibrox club in a summer in which they will want to go under the radar as much as possible ahead of their Scottish Premiership return.