Well, exactly. Roddick only has a retirement total of 4 matches, it's just that they've become particularly notorious because two of them have been in Grand Slams, against Hewitt at RG and Ljubicic at the AO. Incidentally, his other retirement was in the first round of Shanghai against Andre Sa, the man who last year led him by a set and 4-0 in Memphis but still managed to lose the match. Americans seem to be cursed over there in the Far East....
He still has a long way to go to catch up with the all-time retirement maestro Jerome Golmard, who has no fewer than 23 to his name, including his only two matches this year. An analyst once said on TV that the three people whose careers had probably suffered most through injury were Krajicek, El Aynaoui and Golmard - indeed, it's amazing he managed to stay healthy long enough to win a couple of titles in his career. And yet you can't sniff at someone who beats Santoro, Kucera, Henman, Moya and Kiefer all in a row to win Dubai, can you?