Dallas Keuchel may be the most underrated pitcher in baseball this season. (Bob Levey/Getty Images)

In the race for this year's ERA title, you'll find some likely candidates, your Adam Wainwrights and Felix Hernandezes, and you'll find some surprises (hi, Mark Buehrle!), and then you'll find a name that feels like it's there purely by mistake. Tucked in there among the top 10, nestled snuggly between Hernandez and Josh Beckett, is a 26-year-old lefty with the hard-to-pronounce last name who has emerged as MLB's unlikeliest ace. His name is Dallas Keuchel (that's kye-kill, in case you were wondering), and with eight innings of one-run ball against Arizona on Wednesday, he's now boasting a 2.38 ERA for an Astros team that continues to surprise.

The numbers behind Keuchel's season are as impressive as they are unexpected: The 2.38 ERA, eight wins, 90 2/3 innings, a .226 batting average against, nearly as many double plays induced (15) as walks allowed (18). He has two complete games, a shutout and has pitched six or more innings in all but one of his 13 starts this season, and that lone exception was his season opener. He's now posted seven straight quality starts, and his effort against Arizona is the fourth time in his last six games that he's gone eight innings or more; in that span, he's thrown 46 2/3 innings and allowed just six earned runs.

What makes this all so surprising is how suddenly Keuchel has turned from back-of-the-rotation fodder to clear No. 1 in Houston. Almost nothing in Keuchel's utterly pedestrian 2013 — a 5.15 ERA, 79 ERA+, 2o homers given up in 153 1/3 innings — suggested the profile of an ace. True, Keuchel's fielding independent ERA was almost a run lower than his actual mark, but that still amounted to a mediocre 4.25 thanks to a high homer rate (1.2 allowed per nine innings) and a walk rate that was nothing special (3.0/9). And that all came after an even less impressive 2012, when Keuchel was beat up to the tune of a 5.27 ERA in 16 forgettable starts, walking more men than he struck out (39 to 38).

But Keuchel has found his way thanks to better results from his bread-and-butter pitch: The sinker. Throwing it nearly 40 percent of the time in 2014, Keuchel has limited opponents to a .218 average, .298 slugging percentage and .243 batting average on balls in play on the sinker this season, compared to a .304 average, .401 slugging percentage and .355 BABIP last year. His increased ability to throw it for strikes (26 percent of the time last year vs. 31 percent this year) has led batters to swing more often, and when they do, they pound that sinker straight into the ground: His groundball rate of 65.6 percent is the highest among all qualified starters in baseball.

As good as Keuchel's been, there's no real sign that he's been lucky or that his newfound results are unsustainable. His homer per nine rate is a miniscule 0.44, a far cry from last year's 1.2, but Keuchel's done that by giving up fewer fly balls and through better location of his changeup and slider. His .267 BABIP looks ripe for regression, but it's built on a high ground-ball rate and low line-drive rate (14.5 percent). His walk rate is down, his strikeout rate is up, and he's gotten batters to swing more often and make less contact, including a swinging strike rate of 11.1 percent, a career high.

Simply put, Keuchel has succeeded through the tried-and-true formula of throwing strikes and getting hitters to chase and make weak contact. His slider has been a nightmare for left-handers to handle (.200 batting average against), while his change helps him keep right-handers honest. Against Arizona, Keuchel got plenty of swings and misses (14 on 101 pitches), pounded the strike zone (69 strikes, or 68 percent on the night) and mixed pitches effectively (43 sinkers vs. a combined 43 changeups and sliders). The result? Another stress-free outing where just two batters got to second base or past it on the night, and one of those came via an Aaron Hill solo homer that provided the Diamondbacks' lone run of the game.

And just as Keuchel continues to prove that he's no fluke, the Astros continue to show that they're no longer the basement-dwelling pushover of the last two seasons. With Wednesday's 5-1 win, Houston has more wins than Tampa Bay and Boston and is only 2 1/2 games behind Texas in the AL West. And since going a season-worst 15 games under .500 on May 23, the Astros have gone on a 13-5 run, built on the bats of George Springer and Jon Singleton and on the arms of Keuchel and fellow surprise starter Collin McHugh.

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