From 2002 to 2010, Verizon saturated TV with a nondescript guy wearing glasses going to odd places and asking headquarters “Can you hear me now?” After dozens of commercials, he came to be known as Test Man on Madison Avenue.

When Verizon decided to take its advertising in a different direction, Test Man (real name Paul Marcarelli) was given his walking papers in 2011. As Verizon and AT&T slugged it out for supremacy of the cellphone airwaves, Mr. Marcarelli retreated to the New York theater, filmmaking and occasional voiceover work, presumably with a fat bank account.

With its superior network, Verizon continues to hold off AT&T for the top spot in market share, with the lowest churn rate in the industry. But something interesting happened in the middleweight division: T-Mobile passed Sprint, taking the #3 spot. Of course, advertising was examined and a new approach mandated. Guess who got the call?

Test Man has returned as Pitch Man.

From a recent full-page ad in The Wall Street Journal: “Hey, I’m Paul, the guy who used to ask if you could hear me now on Verizon … It’s 2016 and every network is great. In fact, Sprint’s reliability is now within 1% of Verizon. And Sprint is saving you 50% on most Verizon, AT&T, or T-Mobile rates. Don’t let a 1% difference cost you twice as much.”

He couldn’t say that unless it was true, right? Well, he could, but Sprint’s competitors would be screaming. The fine print in the ad says the 1% claim is based on Nielsen data from test drives taken around the top 106 U.S. markets. Remember, the claim is for “reliability,” not whether you’ll get a couple of bars to make that important call from Booger Corners, West Virginia. (In that case your best bet is Verizon.)

It remains to be seen whether Mr. Marcarelli’s endorsement can save Sprint’s bacon, but credit the company with a cost-effective piece of advertising jui-jitsu.