What’s on Tap: Previewing Thursday’s action

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Thursday gives us a few afternoon games and seven night games. The Braves beat the Reds, the Mariners and Rays are still doing battle, and the Rangers and Athletics started not too long ago.

They’re not playing tonight, but I want to talk about the Cubs. Specifically, their run differential. It’s +159, by far the best in baseball. The Red Sox have the next-best at +86, almost half as good as the Cubs. The Cubs are on pace for a +402 run differential, which would be the best in any 162-game season in baseball history. The best run differential of all time was set by the 1939 Yankees at +411, winning 106 of 151 games. According to pythagorean expectation, which uses run differential to figure out what a team’s record “should” be, the 44-20 Cubs have underperformed their record by four games.

The Cubs have the league’s second-best offense, averaging 5.38 runs per game. They’re nothing special in the batting average department, but own the best on-base percentage at .347 and couple that with a solid .424 slugging percentage.

Where the Cubs really make their money, though, is with pitching. Their starting rotation ERA of 2.33 is by far the best in baseball, almost a full run better than the second-best Mets’ 3.17. They can thank reigning NL Cy Young Award winner Jake Arrieta and his 1.86 ERA for that, but Jon Lester is at 1.89, Jason Hammel at 2.26, John Lackey at 2.66, and Kyle Hendricks at 3.05. A typical No. 5 starter has an ERA in the 4.50-5.00 range, just to put Hendricks’ performance in perspective.

Once opponents get the Cubs’ starter after the game, it only gets marginally easier, as the Cubs’ 3.48 bullpen ERA is 10th-best in baseball. Closer Hector Rondon has been among the best in the game, getting the save in 11 of 13 opportunities with a 1.57 ERA and a 32/3 K/BB ratio in 23 innings. Somehow, the Cubs have turned failed starters Travis Wood and Trevor Cahill into reliable relievers and Pedro Strop — the “other guy” in the infamous Arrieta trade with the Orioles — has made significant strides with his control.

Defense is harder to analyze, particularly only 64 games into a season, but the Cubs also shine here — no surprise. Addison Russell, Jason Heyward, Dexter Fowler, and Kris Bryant have graded out as elite defenders. Jorge Soler has really been the only red mark defensively.

Will the Cubs continue to challenge the ’39 Yankees’ all-time run differential record in late September? Probably not. The grind of a 162-game season always seems to level the playing field to some degree. The Cubs, who have had only three multiple-game losing streaks this season, will slump at some point. But they’ve shown they are clearly the top dogs in baseball this season. It will be interesting to see how far they can take it.

Thursday’s action…

Toronto Blue Jays (J.A. Happ) @ Philadelphia Phillies (Aaron Nola)

Baltimore Orioles (Tyler Wilson) @ Boston Red Sox (Eduardo Rodriguez)

Pittsburgh Pirates (Juan Nicasio) @ New York Mets (Bartolo Colon)

New York Yankees (CC Sabathia) @ Minnesota Twins (Kyle Gibson)

Detroit Tigers (Justin Verlander) @ Kansas City Royals (Danny Duffy)

Milwaukee Brewers (Junior Guerra) @ Los Angeles Dodgers (Scott Kazmir)

Washington Nationals (Tanner Roark) @ San Diego Padres (Erik Johnson)