After Masato Yoshii made his third straight ineffective start and heard the wrath of the Shea crowd Tuesday night, Bobby Valentine was afraid his struggling fifth starter would think he let his manager down. In reality, it was the other way around.

Valentine said Yoshii’s recent wildness and inability to find the plate aren’t the problem, but just the symptom of the problem. And Valentine admitted the cause is a slight adjustment that he asked the pitcher to make in spring training.

The adjustment has caused wildness, which in turn has Yoshii pitching from behind and getting smacked around by opposing hitters. In short, Valentine messed Yoshii up.

“Ummm, yeah. That’s what I would say,” Valentine admitted yesterday.

After acquiring Orel Hershiser, Valentine and pitching coach Bob Apodaca told Yoshii to move from the third base side of the pitching rubber to the first base side.

The move was designed to give Yoshii’s best pitch a more pronounced break. Yoshii’s out pitch is called a ‘shuto’ in Japanese, something akin to a reverse slider. But with the recent adjustments, Yoshii’s has been breaking entirely too much.

“I thought it would give it more of an angle,” said Valentine, who added that he’ll have Yoshii move back to pitching from the third base side of the rubber.