It's been a rough two years for Chipotle Mexican Grill (NYSE:CMG) investors, but at least one Wall Street pro is no longer feeling bearish about the stock. Will Slabaugh at Stephens is upgrading the reeling burrito maker on Thursday, arguing that negative sentiment appears to be bottoming out.

The shares buckled below $300 on Wednesday. You have to go back to early 2013 to find the last time that Chipotle stock was trading as low as it is right now. A slow recovery in comps and a another food-borne illness incident have weighed the former market darling down. Chipotle also fell short of sales expectations in its latest quarter. Slabaugh isn't the first analyst to suggest that the worst is behind Chipotle, but all of those that called a bottom before were too early. Slabaugh is the only one who hasn't been burned by upgrading the stock -- so far.

The interior of an empty Chipotle in California.

Image source: Chipotle Mexican Grill.

Bring on the queso

Stephens' Slabaugh isn't bullish on the stock. He's merely upgrading Chipotle stock from Underweight to Equal Weight. However, a reformed bear that is now just neutral on the fast-casual icon will have to do these days.

Slabaugh remains cautious on the competition. A lot has happened during Chipotle's brutal slide that began in late 2015 when the first wave of gastro-intestinal maladies surfaced. Casual dining has embraced home delivery middlemen. Fast food dinosaurs have roared back to life. Even on the fast casual front we've seen consumers flock away from burritos and over to quick-bake gourmet pizza joints that are popping up everywhere. There's a genuine fear out there that Chipotle is slowly awakening from a slumber to find a market that may never be as receptive for its signature eats as it was two years ago.

The analyst is also worried about cost pressures. Margins have taken a beating at Chipotle, and while most of that is the result of falling eatery-level sales relative to the fixed overhead of running its business, we've seen labor and food safety costs escalate at a time when unit sales remain well below where they were in 2015.

However, Slabaugh is excited about the prospects of queso, which the chain is currently testing in New York City. He also feels that improved marketing can help drum up more in-store traffic.

Slabaugh isn't the only analyst to talk up what melted cheese can do for Chipotle. Piper Jaffray's Nicole Miller Regan -- who unlike Slabaugh is actually bullish on Chipotle -- was impressed after a recent visit to Chipotle's NEXT test kitchen that's open to consumers. She noticed that most customers were ordering queso as an entree topping as well as a chip dip. It may not be an ideal sample given the novelty of the item and the fact that consumers are seeking out NEXT because it's the Chipotle that offers queso, but she's ultimately encouraged by a lot of customers paying up for both queso and guacamole -- something that would naturally drum up higher check averages.

The road back will be long for Chipotle, and there's a good chance that it may be trying to find its way to a place that no longer exists. However, with the stock now at four-year lows you can't blame opportunistic investors for giving Chipotle a fresh look.

Rick Munarriz has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Chipotle Mexican Grill. The Motley Fool has a disclosure policy.