think of 怎么不是固定用法?这其实是很常见的用法.不信你随便上Google在英文网页搜一下看.
many a player (who had been highly thought of) has disappeared (from the tennis scene)
who had been highly thought of做定语从句,其中,who代player.这个定语从句又是一个被动式,原型是：
someone had highly thought of whom（即player）.