The football Giants are in trouble, and the preseason hasn’t even begun. They apparently failed to anticipate that they would need to release both Shaun O’Hara and Rich Seubert and are now desperately trying to improve their offensive line. They’ve signed Davis Baas to play center, have moved Diehl to guard and Beatty to left tackle, a position he didn’t excel at last season. To compound their offensive line problems, for their first draft choice in 2011 they selected a cornerback though some excellent offensive linemen were available. Their reasoning: he was a better value. That thinking might backfire this season. As a result of their failure to anticipate, they’re now going after undrafted and waived linemen. Their latest acquisition, Herman Johnson, a 360 pound guard drafted in 2009 who’s previously failed with both the Bears and the Cardinals and has yet to play in an NFL game.