Pleat will assist manager Colin Calderwood with scouting and advice where needed.
He said: "I know in the modern game it is harder for a manager to do everything and to do everything well.
"Colin has to establish himself in one area (with the players) where his quality comes through, or you can become an office-based manager, which is a dangerous thing to do.
"The chairman wants to see you, the press want to see you, there is a player who wants to see you - you have 30 players who want to see you.
"Some players walk out of clubs and say that the manager has never spoken to them. I can believe that, because there is so much going on.
"Colin has to be focused and concentrate on his players and getting results. Colin knows that I am on the phone, that I am available at any time and I am sure it will work because he is sensible. I am a shoulder if he needs it and eyes and ears as well."