FanGraphs: The secret to Livan's success

Livan Hernandez saw his unlikely scoreless streak end at 17 innings yesterday, as he gave up the first of two solo home runs that would give him his first loss of the season. It was the kind of start that serves as a lesson for why wins and losses don't matter, as the Nationals offered no run support. But the loss does nothing to taint what has been the best April of Livan's career, coming in a season where even the most optimistic of projection systems saw him as a 5.00 ERA pitcher. There are a lot of explanations for why Hernandez won't be sustain his success going forward -- his 9-7 strikeout-to-walk ratio, for instance -- but none more so than a hitless streak that would make Ubaldo Jimenez jealous.

Hernandez has pitched from the stretch in 29 plate appearances this season, and in none of those has he allowed a hit. In all, opponents are hitting a ridiculous .000/.138/.000 when their teammates are on base against Livan, which explains why two solo home runs on Thursday are the only runs that have crossed the plate in the 24 innings Hernandez has pitched this season.

At FanGraphs, we track a stat called Left on Base Percentage, which monitors the rate that pitchers strand baserunners. League averages usually hover between 70 and 72 percent, and while better pitchers can routinely be above-average, pitchers of Livan's ilk see a great deal of variance. Stranding runners is a huge part of run prevention, which is why the season Hernandez had his best LOB% (2003 - 78.7 percent) corresponded with his best full-season ERA (3.20). And the year of his worst LOB% (2008 - 64.8 percent) led to a career-worst ERA (6.05). This season, Livan's Left on Base Percentage is a perfect 100 percent, a rate difficult to sustain for three starts, much less an entire season.

In his career, which spans 2,750 innings, Livan has been identical with the bases empty (.780 OPS allowed) and with runners on base (.782 OPS allowed). His stuff doesn't get better from the stretch, his delivery isn't more deceptive. People will say that Hernandez is succeeding because he is "bearing down" with runners on base. This is not true. He is merely in the midst of an amazing stretch of good fortune. While a career revival makes a good story, this is a tale more likely to end with regression to the mean, and another below-average, innings-eating season for Hernandez.

Bryan Smith is a writer for FanGraphs.