Prior to last season, the right field fences were brought in at PETCO Park, and it made a real difference for lefty batters. After being the worst home run park in the National League for lefties by a wide margin in 2012, only Citizens Bank Park and Great American Ball Park had higher home run park factors for lefties in the NL in 2013, according to the 2014 Bill James Handbook.
Among the Padres' hitters, Will Venable and Seth Smith stood to gain the most this season from the park's new dimensions. Smith has taken advantage of them, and then some, as he has hit three of his five homers at PETCO Park (and the other two at Coors Field), while batting .426 there. Venable had a PETCO-fueled power breakout last season, hitting 15 of his 22 home runs at home, but where has the power gone? Everything that could be wrong has gone wrong for Venable, as he is striking out more often and hitting more grounders. Part of the problem is a career-low 72.4 percent contact rate (per FanGraphs.com), but he is also swinging less often and taking more called strikes.
Right now, Venable is not worth owning in standard mixed leagues, but bear in mind that if he improves his contact rate and starts taking a more aggressive approach, he could become a power source again.
As for the Padres' pitchers, righty Ian Kennedy figured to be the one most impacted by his park, and the six home runs he allowed in 47 innings at PETCO Park last year seemed to foreshadow bad things for this season. That hasn't panned out either, as Kennedy has been better at avoiding contact and getting ground balls. When he does allow the long ball, his improved control should mean fewer walks and runs allowed. Barring a reversion to his 2013 form, Kennedy should be safe to start in standard mixed leagues, regardless of where he pitches.