Filling Gene Upshaw's shoes as the executive director of the NFLPA won't be easy.
Who are the possible candidates to be his replacement? Here's one list:
• Former NFLPA president Trace Armstrong: The former Bears, Dolphins and Raiders defensive end is probably the leader. Not only is he a former player, but Armstrong has a good business background. He was president during some of the best growth for the league and union. During his tenure as president, the league brought in new stadiums, sources of revenue and fans. More than anything, though, Armstrong would provide some of the vision that Upshaw had for the future of the league.
• NFLPA general counsel Richard Berthelsen: He immediately was appointed the interim director of the NFLPA. As Upshaw's top lawyer, Berthelsen is the perfect person to get the union through its toughest period in more than 20 years. He knows the workers in the office and the players. His success in the courtroom against owners can't be forgotten.
• NFLPA counsel Jeffrey Kessler: He knows the inner workings of the NFL salary cap and the NBA salary cap because he was involved with the installation of both. Plus, he's an aggressive lawyer in the courtroom fighting for players' rights. Though he will be a prime candidate, he probably will not run for the executive director's position. Like Berthelsen and so many of the people working in the union, Kessler is a close friend of Upshaw. Plus, he also likes doing other work as a lawyer.
• Former NFLPA president Troy Vincent: The former defensive back, a veteran of four NFL teams, was a great player. He's also a successful businessman in the Philadelphia area with several companies he became involved with during his career.
• Former Vikings running back Robert Smith: Over the past year, Smith, one of the league's brightest players, became more involved in the union when some board members were pushing for a succession plan after Upshaw decided to retire. Smith has studied medicine and astronomy. He's bright and has a good business sense. During his playing years, he was part of the union's board.
• Former Chiefs offensive lineman Tom Condon: Besides being Upshaw's agent, Condon was one of his closest friends. He represented Upshaw in contract negotiations with the union's board of directors. One of sport's top agents, Condon has a law degree and has negotiated some of the top deals in the league.
• Candidates from a search firm: At some point, the union's board will hire a search firm to find other qualified candidates. The head-hunting firm could look at labor leaders, business leaders and union representatives from other sports. There is no current timetable set for the hiring of the firm.
John Clayton, a member of the Pro Football Hall of Fame writers' wing, is a senior writer for ESPN.com.