* JC Penney hires outside advisers; sources say Blackstone
* Ackman says he, other shareholders prepared to add capital
* Ackman says Johnson's physical absence hurt
* Says stock may be worth $75/share if sales rebound, costs contained
* Shares close up nearly 5.5 percent
By Martinne Geller
NEW YORK, April 11 (Reuters) - Troubled J.C. Penney Co Inc has hired Blackstone Group LP's financial advisory arm to explore how best to position the firm financially, three sources said on Thursday, while key investor William Ackman said shareholders were willing to put up more capital.
The prospect of financial backing is likely to help soothe investors rattled by the department store chain's controversial decision this week to let go Apple alum Ron Johnson as CEO after a failed turnaround and bring back his predecessor -- whose leadership was also much criticized.
J.C. Penney is seeking $1 billion in cash, according to the Wall Street Journal, which added that options could include selling a minority stake. The company has already been in contact with several private equity firms about a potential investment, two of the sources said.
A J.C. Penney spokeswoman said over the last several months the company has hired outside advisors for "expertise about how to best position the company from a financial standpoint during the transformation".
"It is safe to assume this will continue as part of the work now underway to develop a game plan for the company going forward," she said in an email without confirming Blackstone as the adviser.
Ackman, whose hedge fund Pershing Square Capital Management owns an 18 percent stake in J.C. Penney, told a business luncheon that he does not see a "a scenario in which we don't work this thing out, and we're prepared to put in more capital," he said.
"I've spoken to the other big holders, a number of them, and if the money's needed, the shareholders will put it up," he said although he did not expect his comments to be reported by the media.
J.C. Penney's other big shareholders included Dodge & Cox, State Street Global Advisors, Fidelity and Wellington Management, as of Dec. 31.
The retailer's shares slid 27.6 percent in the first quarter and its troubles have left Ackman's portfolio with some $500 million in losses.
Speaking in New York, Ackman said Penney's former CEO Ron Johnson was not at the company's Texas headquarters enough, since his family lives in California. Even though Johnson worked hard, Ackman said the lack of his physical presence hurt morale.
"The home team lost confidence," he said.
Johnson could not be reached for comment.
This was the first time Ackman, a J.C. Penney board member since 2011, has spoken publicly since his choice to lead the turnaround was dismissed.
Johnson, who joined Penney in November 2011, sought to upgrade the store's merchandise and streamline its pricing structure, which had long relied on coupons. But the moves alienated the store's long-time clientele and failed to draw new customers. The company is now returning to its old strategy of offering coupons.
Ackman described Johnson as brilliant and visionary, but said the team he assembled lacked strong enough operational talent.
"The execution, the basic blocking and tackling of running a retailer -- that's what Ron (Johnson) didn't have," Ackman said. For that, he called out Mike Kramer, the chief operating officer, who he said has left the company. A media report late on Wednesday said three more executives, including Kramer, left J.C. Penney. The company did not confirm Kramer's departure.
The board has now turned to Myron Ullman, Johnson's predecessor. In the past, Ackman had been openly critical of Ullman, saying as recently as last May that the department store operator had been chronically mismanaged and had failed to create value for shareholders for the last 20 years.
What the company needs now though, is somebody who can "stabilize the place" and "calm the vendors", Ackman said, calling Ullman "the right guy at the right time".
At the luncheon, which was sponsored by New York University's Schack Institute of Real Estate and attracted hundreds of people, Ackman had asked for his comments on J.C. Penney to be off the record. No reporters objected at the time, though his comments were soon reported by other news outlets.
Reuters attended the luncheon, which was part of an annual real estate conference at which Ackman is often a panelist.
At the same time Ackman was speaking, a New York state judge urged J.C. Penney and rival Macy's to settle their lawsuit over who can sell home goods bearing the name of domestic doyenne Martha Stewart.
The two companies have been battling since 2011 when J.C. Penney said it would open "Martha Stewart" stores within J.C. Penney stores. Macy's claims it has exclusive rights to make and sell Martha Stewart products.
Ackman did not address the lawsuit.
He did reiterate his belief in Penney's future, saying that if it can get its sales back to where they were in 2011, before Johnson's changes, and keep costs where they are now, its shares could be worth as much as $75 each.
And once the coupons return, Ackman said he expects sales to turn around.
The shares ended up 77 cents, or 5.46 percent, at $14.86 on the New York Stock Exchange.