My apologies, for I know not who Andrew Lonergan is.
From a business point of view, what you say may make sense. But Patricio is still leagues better than Sá. The fact that Patrício is still the Portugal National Team main keeper while Sá was not even in the team for the Euro should be sufficient.
José Sá played for Porto a few years back, while they managed to win the the title, his performance was a bit lackluster. If I'm not mistaken, he had a couple clean sheets for Porto, having suffered 20 goals in 21 games. That's playing for Porto, in the Portuguese league. With a solid defence in front of him against much inferior teams.
I didn't follow his time in Olympiakos, but that culminated with him falling out of the national team as well, eventually. So it can't be that good. Being champions for Olympiakos is not that much of a feat either, as they're the Greek champions by default, only failing to gain the title when they massively screw up.