Today I want to take a look at strand rates, or Left On Base (LOB%), and see if we can learn anything that can help you manage your fantasy baseball roster more effectively down the stretch. I researched this earlier this season, right around the time more major pitching statistics were reaching their stabilization rates. We’re way past that now, which makes it easier to highlight players that are over or under-performing here.

LOB%, as you may have guessed, measures the percentage of base runners that a pitcher strands on base over the course a given time period. This stat does not use the left on base numbers reported in box scores, but instead is calculated using a pitcher’s actual hits, walks, and runs allowed results. It looks like this:

LOB%=(H+BB+HBP-R)/(H+BB+HBP-(1.4*HR))

Most pitchers have LOB percentages around league average (which is 73% this season, but varies slightly from year to year), and pitchers who deviate from the average tend to see their numbers regress towards the mean in the future. In other words, if you see a pitcher with a 60 LOB%, they’re letting more runners score than their FIP would indicate, so their ERA will be higher. The odds are that they will strand more runners in the future and lower their ERA.

Extreme variances from the major league average can be interpreted as luck taking effect, but it’s just as likely that bullpen support, defense, or a pitcher’s natural tendency is responsible. A pitcher’s comfort level with the windup versus the stretch can impact his strand rate as well. It’s important to note that not all pitchers will regress toward the league average, though: high strikeout pitchers, like I recently wrote about Alfredo Simon (82.7% LOB%) as a second half sell, and I’ll continue to beat that drum here today. It’s important to note that Simon has already exceeded his career high in innings pitched, and after throwing just 87 last season, asking him to throw 180-200 innings this season is a big ask. Then you pop the hood and it gets even uglier. The BABIP-against for Simon is .245, and will continue to grow. His strikeout rate is dipping in the second half as well, down to just 15.9%. I’m amazed that he’s been able to pitch this successfully in terms of fantasy scoring. His 12 wins, 2.86 ERA and 1.10 WHIP would be difficult to pass up if it’s on the waiver wire, but that’s exactly what you should do.

Josh Beckett - SP, Los Angeles Dodgers

Josh Beckett makes this list, but with an asterisk. His 86.6% strand rate is the highest in baseball among pitchers with at least 80 innings pitched. Also, his .237 BABIP-against is the fourth lowest total, and more than 50 points lower than his career average of .288. Beckett has bumped up his strikeouts over seasons past, and his 23.1% is his highest total since 2008. The strikeouts are good to see, but the extreme underlying stats referenced at the top make it hard to trust Beckett. The ERA/FIP split, 2.74/4.29, gives us a better idea of what to expect the next two months.