As if there isn't enough upheaval at Subway -- yesterday global Chief Marketing Officer Tony Pace said he was leaving, two weeks after the chain suspended its relationship with spokesman Jared Fogle -- now the fast-feeder is throwing its creative account into a mystery review.

"Subway confirms that it is conducting a closed review of its creative advertising," said a spokeswoman in a statement. "Based on confidentiality agreements, we are not disclosing participating agencies."

Subway's creative work, as well as Hispanic and digital, is currently handled by Boston-based MMB, which did not immediately respond to a request for comment. It's not clear whehter MMB, the agency of record for the chain since 2005, is participating in the review. Other agencies on the roster, such as WPP's MediaCom and Dentsu Aegis' 360i, are not affected, the spokeswoman confirmed.

It's been a tumultuous couple of weeks for the chain. Subway suspended its relationship with longtime spokesman Mr. Fogle on July 7, the same day after federal authorities investigated his home. Authorities did not say why they investigated the home, and Mr. Fogle was not charged with a crime, but Russell Taylor, executive director of the Fogle Foundation, a group that is dedicated to helping teach kids healthy lifestyle habits, was arrested on child pornography charges back in May.

Mr. Pace's departure to form a consultancy called Cerebral Graffiti followed not long after, though Mr. Pace said publicly yesterday that he move was unrelated to the Jared issue.

The agency review comes as the chain is seeking to reverse a sales slide. Subway last year had its first decline in U.S. systemwide sales in years, with a 3% drop, according to Technomic. Though sales were down, store count was up almost 3% in the U.S. in 2014, though, to 27,205.

Much of Subway's broadcast advertising has over the years has focused on a mix of Mr. Fogle, value advertising and more recently, promotion of premium-priced products. Though Mr. Fogle has appeared in recent ads, he hasn't been featured as prominently as he once was, as the chain diversified its marketing and incorporated its Famous Fans. The promotion of more premium sandwiches that include ingredients like avocado came sometimes at the expense of the marketing for its $5 footlongs, a product that brought in cost-conscious customers.

Subway in 2014 spent about $533.2 million on U.S. measured media, according to Kantar Media, up 3.5% from $515.2 million.