Yes, I'm a little concerned about Greene's game long term, too. The swing seems to generate a lot of torque on the back. The gait, as you mention. One of those two by itself is one thing. Both of those variables together is another. Let's also factor in that he is a weaker armed OF. It's tough to know exactly how this team will look 3 seasons from now, but will Greene be a DH sooner than we think he might? Ideally Clark would be up by then and if Meadows were still around, well, that's a pretty good 2/3 of OF defense right there.
Just in the short term, or any term, does that kind of bat path lend itself more to boons and busts?