The power of Scott Boras

OK, one more post roughly related to Alex Rodriguez and his contract--

Tyler Cowen at Marginal Revolution wonders how Scott Boras might be able to command higher prices for his clients than other agents do. J. C. Bradbury is skeptical of this power. Such skepticism is to be expected from economists, who would be surprised to see a single actor fundamentally change the dynamics of a competitive market as Boras is supposed to do, but I don't think you can seriously dispute that Boras has fundamentally shifted prices at times, especially in the amateur draft.

Cowen lists some mechanisms by which Boras might beat his market, but he neglects what I consider the most interesting possibility: that Boras actually makes his players better. This recent story in ESPN the Magazine describes the ways in which Boras tries to increase the skill and durability of his players. An ability to increase durability seems plausible to me, and if it seems plausible to owners, it may well cause them to pay more for Boras's clients. In the case of A-Rod, durability is a crucial factor, arguably the crucial factor, even a decisive one: if he stays healthy, he will almost certainly become the home run king. I can easily imagine Boras's longtime management of Rodriguez's training regimen being worth millions of dollars to a team.