It stands to reason that a sequel would be adapted from the second book of Dante's Divine Comedy, Purgatorio, which (like Inferno) has a special place for each of the Seven Deadly Sins.
Furthermore, Gamasutra lists the job for the PlayStation 3 and Xbox 360, matching Dante's Inferno's platforms. Dead Space 2 also carries a PC SKU further ruling out Visceral's other franchise.
"The Games Label at EA is 100% committed to this IP, and the IP into film, television, comics, graphic novels, action figures, and the web," reads the posting. "The game sequel will set new quality standards and make the franchise the world-leader in the action/melee-combat genre." Dante's Inferno, of course, featured copious amounts of melee-combat.
While this is not a confirmation that Dante's Inferno 2 is in development, the evidence certainly appears stacked in its favor. Given the timing of this job posting, it's interesting that nothing was announced at E3 2010 if Dante's Inferno 2 is truly in development. However, it's quite possible that EA and Visceral wanted to spotlight Dead Space 2, which is due out next year.
Shacknews has contacted Electronic Arts for comment, but none was available at the time of publishing.