A sudden and rapid appreciation by this group is unlikely, to say the least. The findings of MLB aging curve studies are consistent: players get worse as they get older. In a study by Jeff Zimmerman of FanGraphs, players from 1995 to 2005 showed a steady increase in home run production before tapering off after their 30th birthday . From 2006 to 2013, the curve changed to a consistent decline that began closer to age 25. In other words, in the post-PED era, a player’s power production is immediately on the downswing after he hits his 24th or 25th birthday.
Nevertheless, even ardent proponents of PRP therapy admit that it’s still too soon to know for sure if the treatment is actually effective. (As one surgeon told me, “As soon as I walk into the room with a patient, they’re going to experience a big reduction in pain. A lot of people in these trials want to get better, and that makes all the difference.”) Sampson himself notes that inconsistencies in the application of PRP therapy — some doctors use lower platelet concentrations, or inject the blood in the wrong place — make it difficult to properly assess the treatment. As a result, modern medicine remains dependent on human guinea pigs like Kobe and A-Rod, these professional athletes willing to spend tens of thousands of dollars on unproven medicine.