A Smith's Food & Drug Centers executive Tuesday termed the resignation of Stuart Rosenthal after only 10 months on the job as "nothing special; he just wanted to do something else."

Robert Bolinder, executive vice president of Smith's, stressed that Rosenthal was not pushed out as the No. 2 executive at the Salt Lake City-based retailer but left of his own accord.Rosenthal could not be reached for comment Tuesday. His telephone number is unlisted.

Rosenthal joined Smith's in January, replacing Richard D. Smith, who became vice chairman of the board. It was the first time that the company had gone outside the Smith family for top executive talent.

Bolinder said Rosenthal will not be replaced as president and chief operating officer. Instead, Jeffrey P. Smith, chairman and chief executive officer, will take on the additional duties of president and COO.

"Jeff Smith has decided to take a more active role in running the company," said Bolinder. "He had been backing off earlier, and now he wants to get more active."

Rosenthal's resignation Monday was seen by some as further evidence of serious problems at Smith's, which last month reported a decline of 17 percent in third- quarter net income and a decline of 14 percent for the first nine months compared to the same period last year. Same-store sales for the three quarters were down 3.6 percent from the 1994 period.

Also, on Nov. 3, Smith's said it would lease its new distribution center in Riverside, Calif., to a competitor and last week acknowledged it is considering selling or leasing its 34 stores in the highly competitive Southern California market.

Bolinder said Rosenthal's resignation was not related to the troubled California operation.

"Stuart was responsible for the company's overall operation, and California was just one aspect of that," he said.

Bolinder said he understands that recent developments at Smith's have created the appearance of a crisis.

"It's only natural. But we are evaluating our opportunities there (California) to decide whether to continue or move out of the state, so that has people upset," said Bolinder.

"But we are doing better each day and continue to make pro-gress. Actually, we are pleased with our operation there. It's right on schedule, and if we do decide to stay, it will be more profitable."

Smith's has leased its new Riverside distribution center to Ralphs Grocery Co. and will supply its Southern California stores from an Arizona warehouse.

Smith's built the 1 million-square-foot distribution and dairy center in 1993 to support an expansion that initially was to include 60 California stores.

It has opened only 34 stores. The Riverside distribution plant, a state-of-the-art facility built to supply 100, is operating at only a third of its capacity.

"The logical thing was to get out from underneath the burden of operating a facility under capacity," said Bolinder.