Camped out in deep left field, Lucas Duda waits for a pitching machine to spit baseballs at him. He runs forward, snags a ball at his feet. He runs sideways, grabs a ball near the line.

It is not the most effective use of his time, Duda will admit later. In this artificial replication of the outfield experience, there is one sacred ingredient missing: a baseball bat.

Duda prefers simulations where one of his coaches – Tom Goodwin, for example – uses a bat to hit him line drives and pop-ups. That drill produces a more accurate reflection of the fly balls Duda will need to run down come April.

“You can read the bat,” Duda said while sitting at his Tradition Field locker earlier this week. “You can’t really read the machine.”

Duda, like those fly balls that emanate from the pitching machine, has always been a difficult read. Is he the promising young slugger who hit .292 with 10 home runs during a 100-game run in 2011? Or is he the slump-shouldered problem child who smoldered when the team demoted him to Class-AAA Buffalo last season?

He spent over a month in the minors. When he returned, according to Mets manager Terry Collins, he made it clear he had no intention of taking a shuttle to the minors ever again.

“And that’s great,” Collins said. “I loved it. I loved everything he said. Just before the conversation was over, I said, ‘Now go show me.’ ”

The Mets have pulled the plug on a failed attempt to stick him in right field, a square-peg, round-hole situation that plagued Duda last season. One advanced statistical category measures how many runs above or below average a player was worth as a fielder over 135 games. Last season, during the 81 games he spent in right field – an admittedly small sample size – Duda’s number was a minus-26.