Players trying to coach are still just players. No matter how good they are. Yes that 'player' may know everything there is to know, but the task of coaching is not just knowing but being able to connect with the players you coach to bring out the best in them, which is another skill altogether. You need to concern yourselves with many more issues that are always in flux and adjust on the fly often with little time to make decisions. That being said it can be taught, but there is not any guarantees a player turned coach will have the save level of success as when they were a player. Any argument to the contrary is like saying a well regarded coach could go and play at the same level, just give them some pads and a helmet. Think Bill Belichik could work his magic on the field and not the sideline. Pffft what a joke. Mike Singletary is a great example. Great player, one to be respected for his on-field play. As a coach he never figured out how to connect with his players well enough and as a result he lost them and eventually his job. It had less to do with him knowing the X's and O's, which is a foundational piece for any football coach. He was missing the other elements or characteristics a coach needs, which players often undervalue when making such a switch. If you walk into any new position thinking you know everything, you are only settign yourself up for failure. Props to my man Ed Reed for being wise and choosing a good situation to test the waters of coaching. I wish him the best and know that when the time is right, if things are working well as a coach he'll find his way home to Baltimore.