Bob Nightengale

USA TODAY Sports

Dave Stewart, former general manager of the Arizona Diamondbacks, has joined Massachusetts businessman Tagg Romney’s ownership group bid for the Miami Marlins, a high-ranking baseball executive told USA TODAY Sports.

The executive spoke only on the condition of anonymity since Romney has not publicly announced the addition of Stewart to his group, but Major League Baseball officials have been informed that Stewart is among the new investors.

Romney’s group, which already included five-time 20-game winner Tom Glavine, is one of the two finalists to buy the Marlins along with the group led by former Florida Gov. Jeb Bush and former New York Yankees star Derek Jeter.

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The two groups have already made bids in excess of $1.3 billion that are being evaluated by MLB, but one executive with direct knowledge of the process said that Romney’s group made a higher bid.

Stewart, a four-time 20-game winner, also quietly was bidding for the Marlins with his own group of investors, and now most of his investors will also be joining Romney’s group. It’s believed that Stewart would be in charge of baseball operations if Romney’s group is approved by MLB, joining Magic Johnson of the Los Angeles Lakers as the only African-Americans to have partial ownership of a baseball franchise.

“We have two very strong groups that we believe will have sufficient financial resources to complete the sale and run the team effectively,” MLB Commissioner Rob Manfred told the Miami Herald on Tuesday.

Romney, 47, the son of former presidential candidate Mitt Romney, is the founder and partner in Solamere Capital, a private equity firm. He previously worked as the head of marketing for the Dodgers.

Stewart, 60, the 1989 World Series MVP, has vast front-office and coaching experience since his retirement after the 1995 season. He worked as special assistant to GM Sandy Alderson of the Oakland A’s, special assistant to Kevin Towers of the San Diego Padres, assistant GM of the Toronto Blue Jays, and GM of the Diamondbacks.

MLB is expected to determine which bid will be accepted before their next owners’ meetings in New York on May 17-18.

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