I don't know what to make of this player. He hustles. There's debate about his defense, but he is clearly excellent in LF and IMO decent in CF.
He's hitting .270, one of the higher BAs on the team. Yet he has a .305 OBP, has walked only 6 times in 159 at bats, and has a .670 OPS.
Earlier in his career, he hit righties a lot better than lefties. Last year, he had an .865 OPS against righties; a .553 against lefties. This year, the opposite: he has an .805 OPS against lefties, and a .637 against righties.
In 159 at bats, Heisey has 1 homer this year. Last season in 279 at bats, he had 18 homers.
Maybe he's still a victim of small sample size and it will just take longer and more consistent playing time to see what kind of player he is. Talented player, but there's no consistent pattern with him.