Major League Baseball may find it difficult to penalize Alex Rodriguez, Ryan Braun and the 20 or so other players linked to Biogenesis, even with ESPN reporting the expected cooperation of the clinic’s founder, Anthony Bosch.

The Players Association publicly got involved Wednesday and acknowledged MLB’s plans to speak with those players in its ramped-up investigation of Biogenesis, the alleged performance-enhancing drug-distributing clinic.

“The commissioner’s office has assured us that no decisions regarding discipline have been made or will be made until those interviews are completed,” Michael Weiner, the union’s executive director, said in a statement.

The union pledged its defense of the alleged PED offenders.

MLB officials intend to start interviewing players by the end of this week, according to the ESPN report. Suspensions could potentially be handed down in two weeks, but appeals and lawsuits are expected to follow.

“I think they are on very, very shaky ground,” said Don Maurice Jackson, an Alabama-based sports attorney. “To credibly suspend a player for 50 or 100 games — and you don’t have a positive test — under a collective bargaining agreement, I think the answer to that would be no.”

Notes

• Drug agents are investigating a suspected marijuana shipment mailed to the suburban home of Cleveland closer Chris Perez. No charges have been filed.

• Nationals RHP Stephen Strasburg was placed on the 15-day disabled list with a strained muscle in his back.

• White Sox RHP Jake Peavy will miss at least the next four to six weeks after an MRI revealed he has a fractured rib.