Almost every team has a player or two that is below average, and finding a position for these players can be a real difficulty for the coach. Regardless, each player deserves quality-playing time but the problem is that weak players are often easily exploited and the level of play might drop off considerably when they come onto the field. The question becomes, where is the best place to play these players?
I think the general rule is to play these players on the outside of the field, preferably at forward. Playing them at defense is simply too great a risk, because if they are considerably weaker they will be likely to get beat and it will cost you a goal. If you play them up front, they won’t necessarily help you, but they can’t hurt you either. This will assure that the drop in play is minimal when the weaker players are in the game.
If you plan on playing a weaker player in the midfield, make sure you have an above average defender behind them, and if possible a superb center midfielder who can pick up some of the slack. If you are playing a 4-4-2, outside midfield is a perfect position for the earlier described player.
I also recommend taking the time to analyze the other team to see who their weakest players are, and if possible match your weaker players up with their weaker players to neutralize the chance of your player being exploited. This is good for your team and the other team, and will give both players a chance to play against someone that is at or near their skill level.
My last piece of advice is never say anything to your team about one player not being as good as the others players on the team. First, it will destroy the confidence of the weaker player making it all the more likely they won’t improve, and it will give the other players on the team a reason to doubt them.