From the Biz Of Baseball.com :

The days of advertising medications that address erectile dysfunction along with sports are on the wane, with MLB being one of the causalities.

Viagra is ending its five-year sponsorship with MLB, which had Palmeiro as the first athlete to endorse as well as admit to using an ED drug. As reported by Terry Loften of the Sports Business Journal :

œWith changes in pharma TV guidelines, Pfizer literally could not activate the [MLB] sponsorship in prime-time advertising any more, said a marketer familiar with the situation. œSo they are out of baseball and probably out of sports altogether.