With the cable industry in the doldrums, at least one consultant expects companies such as Comcast (CMCSA), Time Warner Cable (TWC) and others may be headed for some downsizing. Shahid Khan, partner at IBB Consulting Group, recently said he thinks the big cable operators are going to spend the next two to four quarters focused on “operational efficiencies.”

“They’ve had the happy problem of growth,” says Khan. “Now that’s slowing down.”

Indeed, Time Warner Cable, whose biggest shareholder is CNNMoney parent Time Warner (TWX), today reported larger-than-expected declines in video customers, and missed some analysts’ profit estimates. Time Warner Cable’s lackluster numbers come two weeks after Comcast reported similarly uninspiring results, prompting investors to sell off the stock. Both companies’ shares are trading at or near their 52-week lows.

IBB’s Khan says the cable operators are in a bit of a holding pattern. They grew rapidly thanks to the offering of residential voice service and high-speed Internet, bundling those services with their core video product. But they’ve yet to debut the next big part of the bundle (and engine for additional growth): wireless service.

Where’s wireless? The cable operators have a joint venture with wireless operator Sprint Nextel (S) essentially to resell Sprint’s service to cable customers, but according to industry sources, that venture isn’t going well. The parties apparently are squabbling about a number of issues, including responsibility for customer service, among other details. It doesn’t help matters that Sprint is without a CEO. The cable guys also have acquired wireless spectrum but haven’t announced plans to build out a full-fledged network using those airwaves.

Meanwhile, the phone companies such as Verizon (VZ) and AT&T (T) are not standing by while cable grabs their phone and DSL customers. The telcos are fighting back with video products of their own, and apparently are having an impact in several key markets, such as the New York suburbs, Dallas and L.A.

And so Khan predicts some “network efficiencies” at some cable operators in the coming year. Our experience is that, when cable guys start talking about operational efficiencies, it usually means layoffs.

But he also sees some new products coming online that can help cable grow until their wireless strategies coalesce. He thinks switched digital video, a technology that frees up additional bandwidth on the cable network, will help operators deliver more high-definition channels over their pipes. And more high-def, argues Khan, should help the cable operators fend off competition from both phone and satellite companies touting their high-def offerings to lure cable customers.