A new book about Yankees slugger Alex Rodriguez and the Biogenesis scandal alleges Major League Baseball allowed Rodriguez to use performance-enhancing drugs in 2007 and 2008.
In 2007, Alex Rodriguez -- then 32 years old and in the middle of a $252 million contract -- led the American league in home runs, RBIs and extra base hits. He also hit his 500th career home run and won the Most Valuable Player award for staggering number he put up that year, reports CBS News correspondent Don Dahler.
But those historic achievements, according to the new book "Blood Sport: Alex Rodriguez, Biogenesis, and the Quest to End Baseball's Steroid Era," were aided by testosterone, a banned substance that promotes muscle growth.
Rodriguez was permitted to use testosterone, authors Tim Elfrink and Gus Garcia-Roberts said, after requesting a therapeutic use exemption, or TUE.
"In 2007, of the 1,354 players subjected to testing, 111 were granted a TUE. Only two, apparently including Rodriguez, received an exemption for 'androgen deficiency medications,' the category that would include testosterone," the book said.
CBSSports.com' Jon Heyman said exemptions are granted for valid medical reasons and that Rodriguez may have needed the hormone because his body stopped producing it naturally -- a possible side effect of past steroid use.
"We can't be sure exactly what the reason is he needed it medically, but that's often the case -- it's because you're taking it synthetically when you shouldn't be," Heyman said. "We know he was using, because we know he failed that test in 2003."
After the 2007 season, Rodriguez denied to "60 Minutes" he had ever used or been tempted to use steroids, human growth hormones or performance enhancing substances.
The book said Rodriguez got another exemption in 2008, this time for clomid, a drug that can boost testosterone levels.
The book's authors said proof that Rodriguez got the exemptions are in the transcripts of his confidential arbitration hearing last fall.
Rodriguez is currently serving a season-long suspension, and his spokesperson told "CBS This Morning," "We have turned the page from this and are looking towards 2015 and getting back on the field."