By: Liz Farmer

On Sunday, NBA big man Shaquille O’Neal faced off with Baltimore’s Olympian Michael Phelps in a swim-off for ABC’s new reality show, “Shaq Vs.”

Phelps, an eight-time gold medalist at the 2008 Summer Olympics, and Shaq, a perennial All Star with a playful personality, squared off before a crowd of about 600 at the Loyola College of Maryland.

“Shaq Vs.” debuted last Tuesday, but didn’t make much of a ratings splash among the big four networks; it barely edged out Fox’s “More to Love” (4 million viewers) with a total 4.3 million viewers. That’s less than half of NBC’s “America’s Got Talent” (11.6 million) and CBS’s “Big Brother” (8.1 million).

Last week’s episode featured Shaq battling it out with Pittsburgh QB Ben Roethlisberger. I imagine they’re hoping for more of a ratings spike with Phelps, whose reputation (good or bad) is more widely known outside of the sports world.

ABC previously partnered with O’Neal on the 2007 summer reality series “Shaq’s Big Challenge,” in which he coached overweight kids on how to develop a healthier lifestyle. After disappointing ratings, however, the show didn’t return for a second season.

I’m not sure if the problem is Shaq or the crowded field of competitors. “America’s Got Talent” and “Big Brother” are some pretty stiff competition to go up against. I expect Phelps’ appearance in this week’s episode should give the show a ratings boost — if not, Shaq could have another dud on his hands.