Jonny Gomes has a message for Alex Rodriguez: Don’t mess with the Major League Baseball Players Association. “He does steroids or whatever, it sucks. He does this or that, it sucks. He’s always in the news, it sucks,” the Red Sox left fielder told the Herald yesterday before the 75th annual Boston Baseball Writers’ dinner. “But this is the players’ union he’s going against. It’s all of us. Not a real good idea.” Rodriguez recently filed a lawsuit against the MLBPA and Major League Baseball in an attempt to overturn a 162-game suspension for his violation of the league’s performance-enhancing drug policy. It was expected that the embattled New York Yankees third baseman would take action against MLB, but turning against the union has irritated many players in the rank and file, including Gomes. The union represented A-Rod in his arbitration hearing last fall, but Rodriguez’ suit claims the MLBPA “abdicated its responsibility” to defend a player and even takes issue with former union chief Michael Weiner, who died of brain cancer in November. “I think what he had going on is pretty individual,” Gomes said. “He did it. It was his decision, his suspension. But I don’t think it’s really a good idea to go after our union. Down to my (expletive) kids, down to the benefits we have, down to our retirement fund, the union makes our lives better. We pay dues to the union for our rights.”