Phil Hughes is exercising in a pool and experiencing no problem with the bulging disk in the upper back. Nevertheless, he doesn’t know when he will test it on the mound. Manager Joe Girardi said Wednesday Hughes may not be ready to go when the season starts. “Is it in jeopardy, his start? It’s possible,’’ Girardi said. “But it’s too early to tell that.’’ Hughes knows every day away from the mound isn’t good. He likely won’t be cleared to start throwing before the weekend, but he isn’t looking to accelerate the program. “It’s a double-edged sword, I don’t want to push this thing and have it become an on-going issue,’’ said Hughes, who suffered the injury covering first base Feb. 18 during a fielding drill. Girardi said he believes if Hughes gets four starts and gets up to 75 pitches, he can be ready for the season. “I need as many [starts] as I would have gotten,’ ’said Hughes, who appeared in five games [two starts] last spring and worked 17 ***1/3** innings. That was good enough for him to start the third game of the year. “For some reason, if I get to 70 pitches and I feel like I am ready to go, I am ready to go, but it’s not my call.’’ If Hughes isn’t ready to start the season it would mean David Phelps and Ivan Nova would make the team. *** Players Association head Michael Weiner strongly indicated representatives of his office have talked to Alex Rodriguez and Francisco Cervelli regarding their names being linked to Biogenesis in Miami. “I believe members of our staff at this point have met with those players,’’ Weiner said after meeting with the Yankees at George M. Steinbrenner Field. Cervelli said somebody from the Players Association recently visited him in the Yankees’ camp.