NEW YORK (Reuters) - Power market veteran Paul Posoli has returned to JPMorgan Chase & Co. after a year-long sabbatical to help advise on the bank's sale of its physical commodities business, according to an internal bank memo. Posoli, a senior trading executives who rose through Enron and utility giant Calpine before building a formidable gas and power trading division at Bear Stearns, will serve on the commodity unit's management team in an advisory capacity, according to the memo from commodities chief Blythe Masters, a copy of which was seen by Reuters. Posoli, who ran the bank's global gas, power, coal and emissions business until his hiatus last year, is also expected to be part of the new entity's management team if the division is sold as a "new, going concern", according to the memo. "It need not be said that we are extremely fortunate to have someone of Paul's caliber, expertise and knowledge of the industry be integrally involved in charting the future of our business," she wrote. "His decision to return, in and of itself, is a vote of confidence in the value of the business that we have built." John Anderson will continue to run JPMorgan's global gas and power business, the memo said. His return may bolster efforts to sell the sprawling division, which JPMorgan is quitting amid searing regulatory scrutiny and public criticism, as well as an industry-wide downturn in margins for the capital-intensive trade. Several industry sources, including two people who have worked with Posoli, said he is highly regarded in the energy trading industry and is a smart and hard-working leader. Masters, a life-long JPMorgan banker who spent billions building the commodities group into the biggest if not the most profitable on Wall Street, may also remain with the physical commodities unit after the sale, sources have said. Posoli left Enron in 1999, several years before it collapsed, to join Calpine, where he helped build out a major power trading platform. He later joined Bear Stearns, transforming it within years into one of the biggest U.S. power and natural gas traders until it was bought by JPMorgan. (Reporting by Jonathan Leff, additional reporting by Jeanine Prezioso and Eileen O'Grady in Houston; Editing by Gary Hill and Ken Wills)