It is a fact of life that players will suffer injuries during the course of a season. With limited roster sizes and a crowded schedule of games coaches can feel pressure to rush players back to playing. It can be difficult to watch your teams struggle when the addition of a couple of key players out injured could make the world of difference.
I come at this strictly from a coaches perspective. I have played and coached at the college and youth level and have gained some experience on this subject. I have had short-term and long-term injuries myself. I have also talked to doctors, trainers and players about injuries and how to deal with players returning from them. I try to have an in or out policy. If you can participate in training you can do so at 100% with no restrictions. If you can not participate at 100% with no restrictions you should be limited to running or work on the side if permitted. For me there is no "I can play for 10 minutes" or at 50%, etc...
I look at injuries in two catagories.
1. Short-term Injuries - strains, sprains, mild concussions, etc...
2. Long-term Injuries - broken bones, ligament tears and other serious physical injuries
In the case of short-term injuries I have found that when a player feels 100% they should wait another week or two before they enter training. When first coming back players from muscle strains, sprains and mild concussions players will feel good, but need that additional week or two to help combat a re-aggravation of the injury. It is important that the player gets meaningful full speed training in before returning to game action.
In the case of long-term injuries it is important that you require the player to train for 4-6 weeks at 100% with no restrictions before introducing them into a game situation. This is for physical and mental reasons. Cleared does not mean ready to play. Cleared means ready to return to training. Players should look comfortable and confident before playing in a game. When dealing with female players, ACL and serious knee injuries are a major issue. Re-injury happens, but can be minimized by a proper plan in integrating the player back into your team.
It is the responsibility of coaches in the case of both types of injuries to look out for the long-term well being of the player and not the short-term gain of the team. Finally, I encourage players to be responsible and mature enough to be honest about their injuries and their ability to play at 100%. Unfortunately, sometimes as coaches all we have is the word of the player and the parents to make our decision.