Over the previous two seasons, Smith has held a AB/HR rate in between 21 and 22 at-bats per home run. That pace, laid out over 500 at-bats, would translate to about 23 or 24 home runs. This season, however, Smith's home run pace has slowed to about one home run every 32 at-bats. Some of that may be due to the fact that he has faced more left-handed pitching this season than ever before, causing him to have to make more adjustments from day-to-day. Smith hasn't hit lefties very well over his career and he has hit only .246 off of them so far this season with only one of his 12 homers. Lately, Smith has rode the pine against lefties more often than not, which could actually be a good thing.
Fantasy GMs in weekly leagues may not be able to take advantage of this, but if you're in a league with daily roster moves you can definitely make use of Smith's best attributes. He can flat-out mash righties, having put up a .297 AVG and .528 SLG so far this season. His HR/FB rate against right-handed pitching -- about 11 percent currently -- is actually down from rates he has posted over the last two seasons, so we could see that number jump upward over the remainder of the season.
With Smith not having to worry about lefties as often, he can focus all his attention to crushing right-handers like he has in the past. While this will limit his playing time, it could very well increase his home run production the rest of the way.
If Seth Smith is still available in your format, add him, start him against right-handed pitching and watch in joy as he blasts baseballs over the fence for your team down the stretch.