​September arrives kicking and screaming into this Major League Baseball season, with its dozens of mediocre teams still in contention and just 28 days left to find resolution.No, we are not yet to the point of calling this week’s key matchups compelling. That day might never come. But we will say things are getting moderately more interesting.That’s a start.The coming week will produce a nearly full slate of games every day and just two to four series are virtually devoid of playoff ramifications, and fewer than that if you consider the Cardinals, Pirates and Twins still on the periphery of contention. The rest will have a scent of relevance – and a few are actually pretty important.With that, a look at five of the bigger series this week:Milwaukee Brewers at Chicago CubsWhen: Monday-Thursday, Wrigley FieldKey matchup: Monday – Brewers LH Kyle Harrison vs. Cubs RH Clay HolmesOutlook: The Brewers can more or less ice the NL Central title by taking three of four, which would push their lead to 10 games. And the Cubs likely need a sweep to trim their deficit from eight games to four, at which point they’d have 25 games to try and make up the difference. But the division largely seems like settled business; this one feels more like a couple fighters feeling each other out in the early rounds with larger stakes down the line, such as a repeat of their five-game NLDS last year, won by Milwaukee. In case you wondered, Jacob Misiorowski will pitch Wednesday night, opposed by Cubs lefty David Peterson.Chicago White Sox at Houston AstrosWhen: Monday-Thursday, Daikin ParkKey matchup: Thursday – White Sox RH Luis Castillo vs. Astros RH Hunter BrownOutlook: A clash of division leaders! A potential ALCS preview! Or, a 69-68 club that just fired its general manager taking on a team that lost 119 games two seasons ago. OK, let’s call the glass half full, at least: The White Sox have very much earned their 3 1/2-game Central lead, even if their 72-64 record would be useless in any other division except the West, where the Astros for now reign supreme over a cast of losers. This will be a good test for the Sox, though, getting out of the Central and taking on a club of playoff veterans in what can be a raucous place to play. A Sean Burke-Brown matchup would’ve been entertaining but instead, Castillo, who has a 6.45 ERA in five starts as a White Sox, will try to pull off a reverse lock.Toronto Blue Jays at Cleveland GuardiansWhen: Tuesday-Thursday, Progressive FieldKey matchup: Wednesday – Blue Jays RH Dylan Cease vs. Guardians LH Joey CantilloOutlook: Finally – finally! – a compelling matchup strongly tied to the AL wild-card race. It might take all September for this quagmire to shake free, but at least we have a showdown between two teams that are both playing well and firmly in the race. Cleveland enters the week with a one-game lead over Baltimore for the final wild card, with Toronto lurking 1 1/2 games back. So the Jays are just 68-70,