I think the assumption here is that Valve is considering doing the port in-house.
At this point, LFD is an unproven IP, so diverting resources for a PS3 port now is out of the question, but even having a port done by another studio could be too risky, particularly if it's done as poorly as the Orange Box EA port was.
A bad port would only hurt the game's image, as well as the studio's image for giving the green light on a sub par release.







