Wilmer Flores is already a hard-to-miss figure in the Mets clubhouse, but a few more swings like the one he took against Brandon Lyon yesterday will only increase his visibility. The 21-year-old infielder hit a three-run homer in the third inning that highlighted the Mets’ intrasquad scrimmage at Tradition Field. “When his bat is ready, he will play in the big leagues,” manager Terry Collins said of the 6-foot-3, 190-pound Flores. “I don’t know what position yet, but he will play in the big leagues.” Flores, who has worked out at second and third base this spring, is expected to begin the season at Triple-A Las Vegas. Last season at Double-A Binghamton, he hit .311 with eight homers and 33 RBIs in 66 games after being promoted from Class A. “You saw [Flores] three years ago ... when he was a tall, skinny kid and growing into his body, that the bat potential was huge,” Collins said. “You saw big power back then, even though he was a skinny guy.”