Potbelly’s Sandwich Works with its core markets being Chicago, Washington D.C., and Texas, is walking away from some potential new locations, and renegotiating leases on existing locations to “reflect the new market conditions.”

In recent months the sandwich chain has walked away from at least two prospective deals in the suburbs, in Hillside and Romeoville, and local real estate sources say company executives have told them Potbelly is pulling back its growth plans here.

Potbelly founder Bryant Keil said last year that the chain could double its Chicago-area stores to more than 150, and hired former Sears CEO Aylwin Lewis to spearhead growth nationwide. Mr. Lewis said he wanted to accelerate expansion and at the very least maintain Potbelly’s growth rate of about 40 new restaurants a year.

But the dramatic drop in the economy over the last six months has hit even the private Chicago-based company known for its kitschy décor, toasted subs and fresh-baked cookies. Potbelly’s costs to build its stores are higher than its rivals’, sources say, so the company can’t afford too many mistakes in a climate where sales are likely to be slow.