NEW YORK — Peter Barton’s resignation as Liberty Media CEO, announced quietly late Tuesday night, comes just as the company — Tele-Communications Inc.’s $5 billion cable programming offshoot — confronts some critical strategic and operational questions that could dramatically reshape it.Barton quit Liberty Tuesday, effective immediately, to start his own programming business. He said his departure was unrelated to a management overhaul under way at TCI, and was rather in response to his own “mid-life crisis” and desire to do something different, a point confirmed by TCI spokesman Bob Thomson and people close to TCI. Barton is to be replaced by Liberty CFO Robert Bennett. Thomson also said Bennett would likely be replaced as CFO. Wall Streeters and company execs downplayed the impact of Barton’s departure. Gordon Crawford, a senior VP with Capital Research — a big investor in Liberty and TCI — said Barton had “done a fantastic job,” but noted that Bennett “is a very capable executive” who had worked closely with Barton. “The company is still here,” Bennett told analysts on a conference call. “It will be managed otherwise by the same people, and we expect that we will go continue to go forward without interruption.” Investors were not so sure. Liberty’s stock price dropped 50¢ to $19.50 Wednesday, although the stock price decline may have been more affected by Bennett’s outline on the conference call of some of the issues confronting Liberty this year. Among the things he revealed: * Liberty’s plans to spin off its 9% shareholding in Time Warner Inc. into a new publicly traded company and sever its formal links with TCI through a separate spinoff were “up in the air” because of problems with the IRS. * Bennett also implicitly confirmed reports that Liberty is negotiating to sell both its 50% stake in the Fox sports joint venture and its 20% stake in Intl. Family Entertainment to News Corp. While he refused to comment on the two deals, Bennett said Liberty was a portfolio investor, and was always prepared to consider a good offer. “You shouldn’t be surprised if you see us doing things,” he added. * In coming months, Liberty has to renegotiate its financing of the Starz movie channel, now jointly owned with TCI. “This is a decision-making year for us,” Bennett said. Starz is bleeding red ink as it attempts to lure subscribers with new movie deals — losses now being funded by TCI; but the cabler’s own money problems are expected to put an end to that arrangement. Bennett said the discussions with TCI on changing the existing arrangement had begun, and an announcement of a “solution” could be made in the second quarter. Bennett also told analysts that cash flow growth at Liberty’s Encore movie channel and the sports joint venture would come under pressure this year because of new investment spending in both ventures (although this will be less of an issue if Liberty, as expected, sells out of the sports venture). All this disheartened some on Wall Street. “He is putting a lot of caution on 1997 cash flow growth,” said Lehman Bros. analyst Larry Petrella, who noted that doubts about the two spinoffs makes the prospects for Liberty’s stock “look very questionable.” But the issues also raise questions about the overall shape of Liberty. Aside from its 49% of Discovery Communications and substantial shareholdings in electronic retailers QVC and HSN, Liberty’s major assets are its shareholding in Time Warner, its 50% of the Fox sports joint venture and its interest in IFE, so the deals and spinoffs under discussion could drastically change the company. Some big changes have already occurred. Over the past 18 months, Liberty reshuffled its interests in Home Shopping Network and Silver King Communications into a combined company, HSN, run by Barry Diller, who is overseeing a new direction for the group. Fox has taken over management of the sports networks, and may take over IFE, while Liberty agreed to Time Warner’s takeover of Turner Broadcasting, which translated Liberty’s stake in TBS into a big, but non-voting, stake in TW. Barton told Daily Variety that the changing face of Liberty did not influence his decision to quit. “I think the Liberty story is far from the final chapter,” Barton said, adding that Liberty’s game plan is “to keep trading assets.” Barton refused to go into details about future strategy, but did confirm that Liberty had talked with Fox about selling out of the sports joint venture. “We have had conversations (about the sports venture) but it’s not something I would describe as imminent,” he said. Barton also denied his departure was related to management changes at TCI, where new president Leo Hindery has demoted Brendan Clouston and is expected to bring in a new team. “This was a purely voluntary honorable discharge,” Barton said, adding that “if TCI was in better shape earlier, this would have happened earlier.” Barton turns 46 on Saturday, and had his 15th anniversary with Liberty Tuesday. He hasn’t yet defined his new venture, but said it would focus on exploiting programming opportunities in cable, broadcasting and on the Internet. He will start talking to potential backers next week.