UPDATES: 10/7/13, 11:25 a.m. EDT. The names of the full Proskauer team advising MLB have been added to the 16th paragraph of this story. The New York Times reported Saturday that Rodriguez and his legal team are at odds with the MLBPA, which has been kept out of the loop of his litigation strategy. 10/7/13, 5:50 p.m. EDT MLB has filed a motion to have Rodriguez’s suit removed to federal court, according to ESPN.com, which also notes that further proceedings in his arbitration appeal have been delayed until October 15.

Proskauer Rose, no stranger to advising professional sports leagues and franchises, has been retained by Major League Baseball for a scandal-soaked suit filed Friday by embattled New York Yankees star Alex Rodriguez and his lawyers from Reed Smith, Gordon & Rees, and New York’s Tacopina Seigel & Turano.

As The Am Law Daily reported in August, Rodriguez retained Reed Smith commercial litigation cohead Jordan Siev and investment management chair James McCarroll earlier this year to advise him in his dealings with MLB amid its push to hit the steroid-tainted slugger with a 211-game suspension. By then, Rodriguez was already being advised by sports and entertainment lawyer Wm. David Cornwell Sr., a well-regarded player advocate whose Atlanta-based firm was absorbed by Gordon & Rees last year.

All three lawyers are identified in the complaint filed Friday as representing Rodriguez in connection with the litigation, as is Joseph Tacopina, a high-profile New York criminal defense lawyer also retained by the injury-prone third baseman as he seeks to preserve what’s left of the $275 million contract he signed with the Yankees in late 2007.

The 31-page suit filed by Rodriguez and his all-star legal team in New York State Supreme Court contains a host of bombshell claims, including the allegation that Selig and MLB engaged in a “witch hunt” designed to impugn Rodriguez’s character and cost him millions of dollars in endorsement deals.

The suit is the latest legal salvo fired between Rodriguez and MLB amid the league’s effort to impose a stiff ban on the high-paid Yankee for allegedly violating the joint drug agreement that prohibits players from using performance-enhancing substances as part of the collective bargaining agreement with the players’ union.

MLB moved to punish Rodriguez after he was identified as one of 13 MLB players tied to a South Florida anti-aging clinic called Biogenesis that was the subject of a January story in the Miami New Times detailing the sales of certain performance-enhancing substances to various players. Alone among the Biogenesis-linked players to challenge his suspension, Rodriguez is appealing his ban through an arbitration process that began this week along with the MLB playoffs.

The Biogenesis fiasco is the latest embarrassment to the league’s attempt at image-repair in the wake of a decade of purportedly rampant steroid use that baseball purists claim has soiled the game’s record books and tarred the reputation of one of the nation’s most popular sports. (The rehabilitation campaign began, in large part, with the DLA Piper-backed Mitchell Report in 2008.)

A half-dozen law firms are advising various parties in connection with the Biogenesis fallout, according to our previous reports, with the Major League Baseball Players Association retaining Michael Rubin from San Francisco’s Altshuler Berzon to advise on a probe by the league into the clinics’ relationship with certain players.

That investigation—and a MLB suit filed in Florida federal court earlier this year against Biogenesis and its benefactors—is a central focus of the civil case filed Friday by Rodriguez against the league and commissioner Allan “Bud” Selig.

The Yankees star accuses MLB of paying $5 million to Biogenesis founder Anthony Bosch—who is reportedly the target of a federal criminal investigation—in order to “buy his cooperation” in the league’s case against Rodriguez. The complaint also accuses MLB of other “ethically challenged behavior,” such as intimidating potential witnesses and handing over a bag of $150,000 in cash to Biogenesis’s former marketing director in a Fort Lauderdale restaurant in return for key clinic records.

MLB is also accused of making “a brazen attempt to breach Mr. Rodriguez’s attorney-client privilege” by seeking documents from Miami’s Black, Srebnick, Kornspan & Stumpf concerning its representation of Rodriguez earlier this year. (Name partner Roy Black was initially retained by Rodriguez, but the firm is no longer representing him.)

The suit aims a fair amount of vitriol at Selig, claiming the commissioner has a personal vendetta against Rodriguez, a three-time American League MVP, because of Selig’s own alleged failure to rid baseball of steroid use. “Taking down [Rodriguez] would vividly demonstrate that Commissioner Selig had learned from the errors of his previous explicit or tacit tolerance of steroid use,” the complaint states.

Selig announced in late September that he would retire as the league’s commissioner after the 2014 season. This week Selig promoted to COO Robert Manfred Jr., a former Morgan, Lewis & Bockius labor and employment partner now serving as MLB’s executive vice president for economics and league affairs, making him a potential candidate to become the next commissioner. (The reshuffling of MLB’s executive ranks led the Milwaukee Business Journal to report this week on Foley & Lardner’s client relationship with MLB and Selig, a Milwaukee native whose daughter once worked at the Am Law 100 firm, which hired Manfred’s predecessor Robert DuPuy in 2011.)

In a two-paragraph statement issued Friday, MLB excoriated Rodriguez’s suit, calling it “a clear violation of the confidentiality provisions of our drug program, and it is nothing more than a desperate attempt to circumvent the Collective Bargaining Agreement.”

To contend with the suit, MLB has tapped Proskauer to lead its outside counsel efforts. The firm has already been working closely with Manfred and one of its former partners, Daniel Halem, who serves as the league’s general counsel for labor. Other MLB in-house lawyers working on Biogenesis-related matters include Steven Gonzalez, Patrick Houlihan, and Paul Mifsud, according to our previous reports. (MLB’s general counsel is Thomas Ostertag.)

Proskauer sports law group cohead Howard Ganz, who also cochairs the firm’s labor and employment practice, has been leading a team from the firm advising MLB on the Biogenesis case. Ganz was unavailable for comment Friday. Ganz is now also leading a Proskauer team advising the league in the Rodriguez litigation that includes labor and employment cochair Joseph Baumgarten, labor and employment partner Neil Abramson, and senior counsel Adam Lupion and Evandro Gigante.

The Am Law Daily reported two years ago on Proskauer’s role advising the league in its collective bargaining negotiations with the MLBPA, which has spent a considerable sum on legal bills for its own various performance-enhancing drug legal battles over the past few years.

Rodriguez is also likely racking up his own substantial legal tab by waging what is now a two-front war with MLB in state court and in proceedings before arbitrator Fredric Horowitz.

Some observers, such as NBC Sports baseball blogger Craig Calcaterra, a former litigation associate at Squire Sanders and Thompson Hine, believe that because the tortious interference claims in Rodriguez’s civil case are thin, the suit is merely part of a wider strategy to drive a divide between him and the MLBPA in order to compromise the integrity of the arbitration process, thereby allowing the Yankees star to stake out a higher legal ground and reach a more favorable settlement with the league. (Rodriguez’s complaint cites a blog post Calcaterra wrote earlier this year criticizing MLB’s suit against Biogenesis.)

The MLBPA, whose executive director Michael Weiner is battling terminal cancer, issued a statement Friday noting that it will be reviewing the allegations in Rodriguez’s suit against the league. “The union . . . is currently focusing its attention on Alex’s arbitration hearing,” said the MLBPA. “The union will continue to work closely with Alex Rodriguez and his legal team to defend his rights and the rights of all union members.”

The Yankees—whose president is Akin Gump Strauss Hauer & Feld senior labor and employment senior counsel Randy Levine—were not named as defendants by Rodriguez, although a separate medical malpractice suit has reportedly been filed against team doctor Christopher Ahmad and New York Presbyterian Hospital and Columbia University Medical Center over their treatment of a hip injury that sidelined the troubled Yankee for the first half of 2013.

Rodriguez, who is seeking an unspecified amount in damages and attorneys fees in the suit against MLB, wasn’t the only baseball star to make litigation news on Friday.

Former St. Louis Cardinals slugger Albert Pujols, who signed a $254 million contract with the Los Angeles Angels in late 2011, filed a defamation suit Friday in Missouri against ex-ballplayer and former St. Louis radio personality Jack Clark, who publicly accused Pujols this summer of using performance-enhancing drugs.

Clark, who was fired from his radio show after making the controversial comments, is being represented by Chet Pleban of St. Louis’s Pleban & Petruska. Pujols has turned to high-powered Los Angeles litigation boutique Lavely & Singer.

Separately, Santa Monica’s Kinsella Weitzman Iser Kump & Aldisert, another Los Angeles-area litigation firm, is representing Milwaukee Brewers star Ryan Braun, who was slapped with a defamation suit in July by longtime friend and law student Ralph Sasson.

MLB hit Braun with a 65-game suspension in July over his ties to Biogenesis.