(FORTUNE Magazine) – WITH EIGHT ANGRY MORGAN STANLEY alums--including one former chairman and one past president--mounting a media-driven blitz to oust CEO Phil Purcell, Wall Streeters have noticed that one big name is conspicuously absent from the roster of dissidents. Where is John Mack? As you may recall, Mack was Purcell's most famous adversary after he merged Morgan Stanley with Purcell's firm, Dean Witter, and then lost a bitter tug of war for leadership of the combined company. Mack exited Morgan in dramatic fashion in 2001, went on to head troubled rival CSFB, and left there last June after returning the firm to profitability but clashing with the board of parent Credit Suisse Group over strategy. Now, just because Mack is silent amid the clamor at Morgan Stanley, don't think for a second that he is not interested or out of the loop. He declines to talk publicly, but his friends say he feels vindicated at long last. Ever since leaving Morgan Stanley, where he spent 29 years, Mack has believed that Purcell's tendency to expel executives who challenge him would cripple the firm and lead to his downfall.

So while Purcell struggles to hold on to the helm, Mack, 60, is keeping his shirt clean and hunting patiently for his own next gig. He recently spurned several intriguing overtures. When Spencer Stuart headhunter Tom Neff called to gauge his interest in some high-profile CEO jobs, including at beleaguered Fannie Mae, Mack said he wasn't interested. He told Neff that Fannie, focused on the mortgage business, is too narrow for him. A more tempting invitation came from Goldman Sachs CEO Hank Paulson. Starting with a January lunch that included Goldman president Lloyd Blankfein, Paulson tried to woo Mack to Goldman. Paulson talked in follow-up conversations about giving Mack a vice chairman title and a major role with clients and strategy. In the end, Mack told Paulson he'd rather run his own company.

Could that company turn out to be Morgan Stanley? Given that Mack was key to building the firm and is remembered by many as its "heart and soul," some people would like to see it happen. But it's a far-fetched plot twist in this drama. Purcell has cannily populated the board with directors loyal to him; the only director left over from pre-merger Morgan Stanley and potentially supportive of Mack is London Business School dean Laura D'Andrea Tyson. You can be sure that wherever Morgan's most famous alum goes next, it will be to a company where he feels secure that the board backs him. -- Patricia Sellers