MLB

JOBA VELOCITY AN ENCOURAGING SIGN

SARASOTA, Fla. — After a pedestrian beginning, Joba Chamberlain’s fastball had more mphs to it and the slider was filthy.

There were positives to take from his start against the Reds yesterday at Ed Smith Stadium, where the Yankees copped a 6-3 win. Yet, according to the architect and a talent evaluator, it wasn’t a masterpiece.

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“It was good, but it can get better as far as velocity and attacking the [strike] zone,” said Chamberlain, whose fastball was clocked at 91-92 mph in the first frame, 93-94 in the second, third and fourth and 93-96 in the fifth. “It was the best [outing], but I have to get better.”

Chamberlain said he didn’t tire in the sixth, but his velocity dropped, he lost control of the strike zone and didn’t finish the inning. He threw 87 pitches, 53 for strikes.

“After 70 pitches, he was empty,” a scout said. “But from 50 to 70 he was as sound as he can be. He is a classic power pitcher, who takes a while to get going. The questions he faces is, can he find the next gear when he runs out of gas and when he gets out of whack [mechanically] can he stop the bleeding?”

Though the Yankees plan to limit Chamberlain’s innings to 140, they aren’t going to hook him just because his individual pitch count is high.

“We need to win games,” said Jorge Posada, who caught Chamberlain for the first time this spring. “If it’s the fifth inning and he needs 120 pitches, he better [be out there].”

Manager Joe Girardi said he wasn’t as concerned as others were about Chamberlain’s velocity being between 88 and 92 in his last outing and figured the gun readings would elevate.

“He was 90 to 96 today and he attacked the zone,” Girardi said of his No. 5 starter, who won’t debut until April 12. “I would have liked to get him through the sixth inning but I didn’t want to push it.”

The days when Chamberlain jolts Yankee Stadium with 98-100 mph fastballs are over unless he returns to a one-inning reliever. However, that nasty slider, which he often used to put away hitters in the eighth inning, was on display yesterday in the first. With two on and two out and a 2-2 count to lefty-hitting Jay Bruce at the plate, Chamberlain went inside at the knees, and by the time Bruce swung the ball was at his shins.

“I could feel it coming out of my hand,” Chamberlain said. “I was getting swings and misses with my fastball.

“[The spring] got a lot better as it went along. The first two [starts] were terrible. This is a good one to build on.”

If yesterday was the foundation, the Yankees can rest easily, because the velocity was up and the slider was unhittable. However, if yesterday was the ceiling, the Yankees and Chamberlain will be searching for answers to very hard questions despite the increased velocity.

george.king@nypost.com