Brandon Lowe fixed his swing by fixing his posture:
Last week, toward the end of the ALCS, as Lowe’s slump reached its nadir, he sent a video of his swing to Bledsoe and two others confidants, asking, simply, “What do you guys see?” Each responded with almost the same answer: Lowe’s posture, which is so vital to him generating such enormous power from such a small frame, had too much slack.
ESPN.com
To sum up the change, Lowe had to bring his booty back. If Lowe’s swing is back, the combination of him and Randy Arozarena at the top of the order makes the Rays better than they’ve been so far, and will give the pitching staff a bit more support.