Sources: Two super agents cleared of wrongdoing in Melky Cabrera cover-up probe

An investigation by the MLB Players Association into the embattled ACES agency cleared powerful agents Seth and Sam Levinson in the attempted cover-up of Melky Cabrera's positive test for testosterone, two sources with knowledge of the findings told Yahoo! Sports.

While the union is expected to discipline the agency for lack of oversight over Juan Nunez, the consultant who helped concoct fake websites to explain Cabrera's positive, a memo distributed to ACES clients and obtained by Yahoo! Sports said such sanctions "will not compromise ACES' ability to represent you in contract negotiations."

Furthermore, the memo said the union will not investigate past allegations in the Mitchell Report or from Paul Lo Duca, a former ACES client, tying the agents to performance-enhancing drugs.

Shane Victorino, Jonny Gomes, Everth Cabrera and Nyjer Morgan have left ACES – believed to be baseball's second-largest agency – since Major League Baseball cracked the Cabrera ruse, though their departures are not known to be related to the case. The agency's high-profile players include David Wright, Dustin Pedroia, Jonathan Papelbon and Brandon Phillips.

ACES did not respond to a phone message and email, and the union declined comment.

MLB investigators found that Nunez, who has since been fired, constructed an elaborate cover-up that included a $10,000 payment for a website designers doctored to include a fake product that Cabrera alleged he had used.

[Related: Ultimate free-agent tracker for 2012-13 offseason]

Upon Cabrera's 50-game suspension, the union launched an investigation into ACES, which provided more than 1,000 pages of emails, phone records, personnel records and other documents, according to the memo. The union also spoke with the Levinsons and other ACES employees, a contractor who handles information technology for ACES and two co-conspirators of Nunez. All current employees were cleared of wrongdoing in the Cabrera case.

ACES' cooperation into the investigation, as well as its previous compliance with Agent Regulations, worked in the agency's favor, the sources said.

More news from the Yahoo! Sports Minute:

Other popular content on the Yahoo! network:
Warren Buffett admires LeBron James' business savvy
Y! News: How to help relief efforts for Superstorm Sandy | Photos
Fantasy football video: Monday night predictions for Eagles-Saints
Y! News: The man with the most debt in the world