The Yankees are riding high right now. Sweeping the best team in baseball is, of course, the best possible way to start the second half, and they did it in style, too.

Breaking Jose Contreras’s streak of 17 straight winning decisions on Friday, mauling Mark Buehrle on Saturday, and surviving yesterday thanks to a brilliant two innings of relief from Mariano Rivera is a fine stretch of games to have. It’s one thing to win, another to do so in diverse ways, and still another to do so with the less-than-impressive outfield troika of Melky Cabrera, Aaron Gueil, and Bubba Crosby starting. With 10 games upcoming against Seattle, Toronto, and Texas – all quality teams, none intimidating ones – the Yanks should be in position to put a bit of the vaunted distance between themselves and the Red Sox if things break right.

But, but, but… there are always caveats with the Yankees,a team that can never play up to unrealistic expectations. As impressive a showing as this was for them, it wasn’t necessarily the start of something larger.

The main thing is that sweeping the White Sox right now is not quite the achievement in seems on paper, especially in Yankee Stadium. While wellrounded and deep, the Sox, contrary to the misleading press about their supposed small-ball approach, are built around two things: starting pitching and right-handed power.

The latter, which is the main thing Jermaine Dye, Paul Konerko, and Joe Crede, among others, contribute to the team, is tamped down a bit in Yankee Stadium, something that doubtless led the team into to its startlingly poor performance in the clutch all weekend. Time after time you saw a right-handed Sox slugger swinging from the heels and flying out to right, as both Konerko and Dye did against Kyle Farnsworth in the seventh inning yesterday with the Yankees up by three.

The former is just in a sorry state right now. Contreras pitched well on Friday, but Buehrle is in the middle of a stretch where none of his many pitches are working and he’s essentially throwing batting practice. His ERA has gone up by a run and a quarter in his last three starts (one of which was against the Cubs, the worst offensive team in baseball).The Yanks’ thrashing of him shouldn’t be taken as a sign that a team without a bottom half of the lineup is capable of decimating an elite starter as much as a sign that Buehrle isn’t going well right now.

Similarly, Freddy Garcia is going through a dead-arm period; he may not have pitched particularly well yesterday, but the fact that he was able to last into the seventh inning throwing a fastball that was literally indistinguishable from his change up (and not in a good way) can be taken as an indicator that the holes in Joe Torre’s lineup are taking their toll on the offense.

None of which is to say that the Yanks don’t deserve credit for forcing the point and taking advantage of the White Sox’ weaknesses; just that this does not strike me as a preview of what an October series between the two teams would look like.

The Yankees, meanwhile, showed some of their own weaknesses in the series (in addition to their considerable strengths) and the main one is that there is no bullpen. You’ll often read writers of a certain bent going on about how close games are decided mainly by luck, and while the point is overstated, there’s certainly a lot to it.

In Friday’s game, for instance, you had Kyle Farnsworth taking over from Randy Johnson in the eighth inning and getting the job done; you then had Mariano Rivera come in for the ninth, give up two runs, and nearly allow the Sox to tie the game. Nothing wrong there, but a bad break here and there and the game might have turned out quite differently. And bad breaks are bound to occur with Farnsworth as the only thing near a reliable set-up man right now .Yesterday, having come in in the seventh, he gave up a home run and two singles without getting an out in the eighth, leading to Rivera – who’s now pitched half as many innings as Pedro Martinez has this year – having to come in with the tying runs on base and six outs to get.

Torre deserves a world of credit for being willing to stretch his pitchers out in big games and cut the more unreliable ones out of the picture as much as possible, but there’s a disaster waiting to happen here, particularly as Rivera hasn’t had his annual two-week shutdown period yet. It’s to the point where Farnsworth just doing what he’s supposed to do, as he did Friday, seems like an unexpected stroke of good fortune, the sort of thing on which the team just can’t rely, and where Rivera seems like the only thing keeping the team from collapsing at the end of every game.

Again, these were three good wins against an excellent opponent, and if a few days ago you had to think it was a lock that two playoff teams were coming out of the AL Central, you don’t have to think that now. But while Seattle, Toronto, and Texas aren’t the most intimidating teams, they’re all very good ones, who may even match up to the Yankees a bit better than the White Sox did this weekend. The normal state of things may yet reassert itself,but right now the wise gambler would put his money on Detroit and Chicago ahead of Boston and New York.