UPDATE 2-Zynga's Pincus withdraws from operations amid turnaround

(Adds executive quote, changes stock rise and adds details on bookings)

SAN FRANCISCO, April 23 (Reuters) - Zynga Inc co-founder Mark Pincus is relinquishing the last of his operational duties at the social gaming company starting on Wednesday and retreating to an advisory role as Chief Executive Officer Don Mattrick pushes through a restructuring plan.

Zynga shares were up 5 percent in after-hours trading on Wednesday after closing at $4.42 on the Nasdaq.

Pincus, who remains chairman of the board, has decided to move on from day-to-day operations as chief product officer, Zynga said in a statement. He has been stepping back from the company that once dominated gaming on Facebook with "Farmville" and raked in over $1 billion in revenues, but is now losing users to mobile game companies.

Pincus still has a strong grip over Zynga's management and corporate decisions because he owned 9.7 percent of the company with total voting power of 62 percent as of March 31, according to a regulatory filing last week.

On Wednesday, the company reported a 36 percent drop in March-quarter revenue to $168 million, although that beat analysts' forecasts of $146.5 million.

The number of monthly players continued to fall, slipping to 123 million, or less than half of 253 million at the end of the first quarter of 2013.

In July, Zynga hired Mattrick, the former head of Microsoft Corp's Xbox business, to replace Pincus as CEO. Mattrick has been managing a series of layoffs, cutting costs, reviewing the company's product pipeline and reshuffling top-level management.

Zynga's turnaround plan and push into mobile gaming are starting to take hold, Mattrick said in an interview.

The company posted bookings of $161 million in the first quarter, a drop from $230 million a year ago. After a gap of two years, bookings grew sequentially from the last quarter.

"We grew from Q4 to Q1 and that's the first step to expanding audience you've got to start posting quarter over quarter growth before you can post year-over-year growth," Mattrick said.

The company said it expects to see revenue in the range of $140 million to $160 million in the second quarter of 2014.

Zynga also announced on Wednesday it hired Alex Garden, a former executive of Microsoft's Xbox business, as president of Zynga Studios, a newly created position that will entail overseeing the company's game studio operations.

Henry LaBounta, who has worked at Electronic Arts and Microsoft Studios, has also been brought on board as Zynga's chief visual officer, and Jennifer Nuckles, formerly of e-commerce portal Plum District and Clorox, will become chief marketing officer, the company added.

(Reporting by Malathi Nayak; Editing by Steve Orlofsky, Tom Brown and Andre Grenon)