It is tough finding them players but sometimes lesser ability in players can be made up for if they stay fit an create an understanding in a partnership or unit. I mean most clubs who have success have a very good back 5 including GK, they don't have to be the best players, but with games come's understanding, communication, trust in each others position and lastly confidence that all are doing the same thing.
The team can build off all these things and it create's a bond and a desire to win for each other for a common goal. We need players that are fit and able to play all season if needed or asked, those waiting for a chance have to create competition in training when not picked, then ultimately take a chance when given. By playing the same way the team structure is set with the same aim then if certain players are injured. Too much messing about create's confusion and misunderstanding of what the team are doing. Different players the same results is the key to being successful, TM suffered bad injuries in the CB position last season and it cost us badly.