After Marlon Byrd belted two home runs on Wednesday night to trigger the Mets’ 10-1 romp over the Nationals, he was a grateful man. Not because of the home runs, but because the Mets gave him a chance to prove he still could help a team win baseball games. Amid a joyous clubhouse, Byrd counted himself fortunate the Mets signed him to a free-agent contract after he served a 50-game suspension last year for testing positive for the banned substance Tamoxifen. Known as Nolvadex in the United States, the drug is used by steroid users to prevent the growth of breast tissue in men and to stop post-cycle crashes. When the suspension was announced, Byrd admitted he used the drug after having surgery to treat a condition unrelated to baseball. Nevertheless, he accepted his suspension without complaint and spent his offseason in Mexico hoping to prepare himself to continue a major league career that began in 2003. “I never played winter ball before but after the 50-game suspension I figured I needed to work on my game and get better,” Byrd told The Post. “The suspension started in June so I didn’t play from June until all the way to the end of the season last year. So Sept. 26 I flew down to Mexico and stayed from the beginning of the [winter] season all the way through the last game of the Caribbean Series. “It was different there,” he added. “They don’t speak much English. But once I started learning the culture and learning the language, it got much better.” He still needed a major league team to believe in him and sign him to a contract for the 2013 season. He remains grateful the Mets did.