Why Chicago Cubs starters Jon Lester, Alec Mills are two of MLB’s best pitchers

Usually when GMs, managers and fans get ready for a baseball season, any consistent production from the Nos. 4 and 5 starters is a luxury. In the Cubs' case, it's been an embarrassment of riches through two turns of the rotation.

Through 10 games, the Cubs are 8-2, good for the best win percentage in the National League. One huge reason for that has been the team's incredible starting pitching. Kyle Hendricks set the tone early when he pitched a complete game shutout in the very first game of the season. Now, the Cubs' starters lead MLB in ERA (1.95), batting average against (.156) and WHIP (0.780). They've done all that while also throwing 60 innings, second only to the Indians who have thrown 70 innings.

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At first glance you'd probably think, yeah, that makes sense with Hendricks starting the season the way he did, and Darvish getting back on track with six innings of two-hit ball in his second start. But surprisingly the only two clunkers came in Hendricks and Darvish starts. In fact, the analytics say Jon Lester and Alec Mills, the Cubs' last two guys in the rotation have been two of the most impressive starters in MLB.

Let's start by looking at the ERAs of all starters who have at least 8 IP, since the name of the game is keeping runs off the board. If 8 IP seems like an arbitrary cutoff… well, it is. But it seems like a fair number to assess quality pitchers who have made two starts in this shortened season with short leashes on pitchers. Among those pitchers, Lester and Mills each rank in the top-10 with ERAs of 0.82 and 1.38, respectively, according to FanGraphs.

So how are they doing it? Neither is a power pitcher who relies on strikeouts. In fact, Lester's four punchouts place him tied for fourth-fewest in our split of SPs who have thrown more than 8 IP. Mills' seven strikeouts (tied for 10th-fewest) aren't much better. These guys succeed by keeping guys off the base paths, and not allowing hard-hit balls.

Looking at batting average against, Lester and Mills move into MLB's top-five, according to our FanGraphs split, with each pitcher holding batters under .120. Since we've already established that neither guy is a power pitcher, when we filter further to just show BAA on balls put in play it should come as no surprise that Lester and Mills rise to No. 1 and No. 2 in all of baseball with .118 and .139 marks, respectively.

Great defense, like Javy Baez's tag in Monday's game, certainly helps the pitchers' stats. But the starters also make things easier on the defense by inducing poor contact, regardless of whether the ball is hit on the ground or the air. According to FanGraphs, Mills ranks second in MLB by inducing soft contact on 33.3% of all balls put into play. In addition, he's 11th in MLB with a 54.3 ground ball percentage. Lester ranks ninth by getting hitters to make soft contact 26.5% of the time, although he's 11th in the league in getting batters to hit fly balls 47.1% of the time.

In the end the result is the same, with Mills and Lester combining to only allow four extra base hits in 24 IP. So although they aren't typical "dominant" pitchers that teams like to make their aces, Mills and Lester have been two of the most effective starters in the game.