The release of a new book that documents Major League Baseball permitting Alex Rodriguez to use testosterone prior to the 2007 season created a stir. Now the MLB Players' Association will investigate the role of agents in last year's Biogenesis scandal.

The book, "Blood Sport: Alex Rodriguez, Biogenesis, and the Quest to End Baseball's Steroid Era," will be available for purchase on July 8. One of the co-authors was the reporter who broke the story about the Biogenesis Scandal last year, which was the last steroid/PED scandal to hit Major League Baseball.

Aside from Rodriguez, other notable players were caught being involved in the illegal operation, including, at the time, Milwaukee Brewers' Ryan Braun, San Francisco Giants' Melky Cabrera, and Detroit Tigers' Jhonny Peralta. All of these players served suspensions handed down by the MLB. But now, the Players' Association is wary of these players' agents being involved with the scandal.

The primary subjects of the investigation are the Creative Artists Agency (CAA) in Los Angeles and the ACES Agency in Brooklyn. Nez Balelo of CAA represents Brewers' slugger Ryan Braun and Juan Carlos Nunez of the ACES Agency represented Melky Cabrera when he was suspended in 2012 for testosterone use. Nunez was found to be connected with the scandal, and ten of ACES' clients were connected to it as well.

Described as an "internal union matter," MLBPA general counsel David Prouty told reporters, "We don't comment on internal investigations or whether we're conducting them," in this ESPN article. It's believe the Players' Association will be looking into these agencies to identify whether or not they upheld proper oversight of their agents and their relations with their clients.

Tony Bosch, the operator of the illegal clinic, reached a deal with the MLB last year to cooperate with the ongoing investigation of the scandal. It is believed that over a hundred MLB players were somehow involved with Biogenesis, and the league will continue to probe the matter until everyone who is responsible is disciplined. With the strict suspensions handed down to players, the MLB is hoping to rid the sport of performance enhancing drugs (PEDs).

You can read more about the new investigation in this ESPN article.