NEW YORK -- The best way to determine how the Yankees felt about Hiroki Kuroda's performance Thursday against the Seattle Mariners is to listen to what they were judging it against.

No one was comparing Kuroda's six innings of work in the Yankees' 4-2 loss to the Mariners, in which he allowed seven hits and four runs (three earned) in the first four innings, against the kind of work he was doing over the first half of last season, when he was a legitimate Al Cy Young Award candidate.

No, when asked to rate how Kuroda threw Thursday, both his manager, Joe Girardi, and the man who had the best view of his stuff, catcher Brian McCann, said pretty much the same thing: He was better than last time.

But last time, as I'm sure you'll recall, was a nightmare in which Kuroda was roughed up for eight runs (six earned) on 10 hits, two of them home runs, in a mere 4 2/3 innings.

So judged by that standard, Kuroda's outing against the Mariners was, as Girardi said, "a step in the right direction."

But right now, with the Yankees rotation down two starters and reduced basically to just one arm they can fully trust -- Masahiro Tanaka's -- baby steps are simply not going to be enough to get it done, especially if the lineup continues to hit (or, more accurately, not hit) the way it did against rookie Roenis Elias.

The truth is, the Yankees need Kuroda to pitch like the de facto ace he was for most of last season, when he picked it up for a struggling CC Sabathia and kept the Yankees in contention long after they probably should have been.

This season, Sabathia is still struggling -- his ERA is an unsightly 5.11 -- Ivan Nova is out for the season after Tommy John surgery, and Michael Pineda is down for a month with a strained back muscle. Vidal Nuno and David Phelps are now regular parts of the rotation.

And Kuroda, who was counted on to pitch like a No. 2, can now hardly be counted on.

In the oft-used catchall phrase of Girardi, it's not what you want.

And probably, not what the Yankees can live with for very long.

The Yankees can spin Kuroda's Thursday night any way they like -- McCann made a point of repeating Kuroda's line, as if emphasizing "only three earned runs" would wipe out the memory that it would have been four if not for a lucky bounce that turned Michael Saunders' laser into the gap into a ground-rule double, robbing the Mariners of a run -- but the reality is this was a weak-hitting team he was facing, and Kuroda was in trouble for every one of the first four innings.

It is encouraging, of course, that he settled down and retired the last seven hitter he faced, but still. There are much more fearsome offenses than this to be faced, and the four runs (only three earned, remember) he gave up Thursday could easily be six or eight on another night.

It is tough to precisely pinpoint what Kuroda's problem is. He's never been a flamethrower, and his velocity has remained virtually the same from the beginning of last season till now, roughly 90-91 mph on his four-seam and two-seam fastballs, 87 mph for his splitter and about 85 mph for his slider. And none of the various high-tech pitch tracking websites seem to indicate that he has lost much in the way of horizontal or vertical movement.

And yet, at times there seems to be a lack of life on some of his pitches, particularly an up-and-in fastball that Robinson Cano was able to turn on in the first inning for an RBI double, and another fastball that Justin Smoak just missed relocating into the right-field seats in the fourth inning.

"He didn't pitch horribly tonight," Girardi said, emphasizing the adverb as if he couldn't quite come up with the right word for exactly how Kuroda did pitch. But clearly, the word was not "well."

Neither could McCann offer up much in the way of praise, other than to say, "I don’t think he pitched that bad. I think he was sharper this time than last time. He gave us a chance to win."

But Elias took away whatever chance Kuroda gave the Yankees, however slim. Using a 94-mph fastball, a sharp downward breaking curve and the advantage of being unfamiliar -- it was only his sixth big-league start -- Elias limited the Yankees to five hits after surrendering a leadoff home run to Jacoby Ellsbury. He struck out 10, walked two, and if not for an error by Cano -- who absentmindedly flipped a routine Mark Teixeira grounder to his shortstop, who was not covering, when he easily could have thrown Teixeira out at first and ended the inning -- would not have allowed another run.

That kind of anemic run support Kuroda is used to, from his four years with the Dodgers and for most of his two-plus seasons here. But this type of ineffectiveness from Kuroda is new to the Yankees, who had come to depend upon him as a reliable, if unspectacular, mainstay of their rotation.

Like most pitchers, Kuroda cited inconsistency, and at one point, said he was "thinking too much" on the mound. Finally, he came around to the essence of what ailed him, and truthfully, for four of his first six starts this season.

"Right now, my breaking balls and splits are not working," he said.

Well, without them, there isn't much left, is there? And without Kuroda, the same can be said about the Yankees rotation.

Said Giradi: "It's important for us to get him going."

That's the answer, all right. Now, the question is, how?