BOSTON – As a Thursday deadline to bid for the Boston Red Sox approached, prospective owners of the storied but luckless franchise hurried to round off their investment groups with wealthy backers.

The Yawkey Trust has asked for final bids by Thursday for its 53 percent stake in the team. Experts expect the controlling interest in the team, which owns 80 percent of the New England Sports Network, to fetch up to $400 million.

The group led by former San Diego Padres owner Tom Werner and Maine ski resort developer Les Otten, said Wednesday it had brought veteran baseball executive Larry Lucchino on board as an investor.

Lucchino ran the San Diego Padres until last summer, and ran the Baltimore Orioles from 1988-1993.

“The Red Sox are a national treasure and it would be a privilege to help lead them to a world championship,” Lucchino said in a release.

On Tuesday, The New York Times Co., which owns The Boston Globe, announced it had joined the Werner/Otten group. A day earlier, the group brought in former Senate Majority Leader George Mitchell, the head of baseball commissioner Bud Selig’s latest economic study committee. It has also been in discussions with Florida Marlins owner John Henry, who has talked of selling his team to current Montreal Expos owner Jeffrey Loria.

Other groups are thought to include Cablevision Systems Corp. founder Charles Dolan; local developer Frank McCourt, who is backed by Lehman Brothers; New York lawyer Miles Prentice, who failed in a bid to buy the Kansas City Royals; concession companies Delaware North, owned by Boston Bruins and FleetCenter owner Jeremy Jacobs, and Aramark Corp.; and a group including local concessionaire Joseph O’Donnell, mall developer Steve Karp, and Staples office-supply store founder Thomas Stemberg.

The decision could determine where the Red Sox call home in the coming years. The team has proposed building a new ballpark next to Fenway Park, the oldest and smallest stadium in the major leagues. But Boston city officials have failed to back it.

The Werner/Otten group has floated a plan to renovate Fenway Park at its current site. McCourt, who is developing the South Boston waterfront near downtown, wants to build a stadium there.