"Assistant general manager Tony Siegle was let go by the Washington Nationals on Wednesday after five seasons with the franchise.
Siegle, who specialized in contract negotiations and rules interpretation, joined the team when it was the Montreal Expos, under current general manager Jim Bowden's predecessor, Omar Minaya.
Siegle has been in baseball since the 1960s, working under more than 20 general managers with eight clubs."
That's the skill set that Colletti had and I think he was mentioned as a possible replacement for Colletti when Colletti left to GM LA, because of his past connection with Sabean; I presume when they both were at the Yankees, as Sabean has only been with the Yankees and Giants.
He could come in and train others in taking on these duties, as he should be in his 60's and looking to retire soon anyway. Or he could take on a part-time role when the Giants really need his expertise but otherwise train others to take on the grunt work tasks. There was talk about Evans taking on some of these duties, plus it wouldn't hurt Tidrow and Dobson to learn the skills too, if they have GM aspirations.