GMs and owners of MLB teams must make the best personnel decisions possible. In addition to the importance of hiring a superb manager, they also must accurately evaluate likely new players and gauge their potential to help their club improve and advance to the next level. Of course, financial commitment, availability of funds, and the luxury tax system are primary guard rails in building a club today; just look at the Yankees.
While minor league prospects help reduce costs and risk substantially, only a small percentage of them make it to the big leagues and perform well.