Motherwell boss warns Slane over Celtic move
Winger Slane, 18, quit Motherwell to join the Hoops for a nominal fee on Monday.
Brown, who confirmed he has agreed to be Well manager for the next 18 months, said: "Sometimes it is better for the career to be patient. I told Paul Slane that.
''Okay, if he comes through beyond them then good luck to him, but he would get much more chance of action at Motherwell just now.
"Young guys see the hoops or the blue and get starry-eyed at that."
Brown admitted he made the same error of judgement when he signed for Rangers as a teenager.
He said: "In my own experience, I went to Rangers when I was 17 and that was a mistake in hindsight.
"I was third choice and Jim Baxter was in my position. I was a bit silly."