Cubs’ Game 1 starter might shock fans who thought the choice was obvious

Had you asked any Chicago Cubs fans before the season who the team's Game 1 starter in the playoffs would be (assuming the team made it to October), you would have gotten two answers in response: Justin Steele and Shota Imanaga.

Of course, Steele made it all of 22 2/3 innings before suffering a season-ending elbow injury, thrusting Imanaga into the uncontested ace spotlight. Besides a hamstring injury that kept him out of action for more than a month, the Japanese southpaw has more or less lived up to the distinction, following up his brilliant rookie campaign with a 3.08 ERA in 117.0 innings.

However, the Cubs are reportedly mulling over the alignment of their playoff rotation, according to Patrick Mooney of The Athletic. Indeed, despite Imanaga's strong season, both Cade Horton and Matthew Boyd have forced themselves into the conversation of who the team's No. 1 starter should be come October.

Cade Horton, Matthew Boyd emerging as serious candidates for Cubs' Game 1 starter

With all due respect to Jameson Taillon, Javier Assad, and Colin Rea, there really are just three options for the role of Game 1 starter.

Boyd leads the starting group in innings pitched (159 1/3), xERA (3.43), FIP (3.38), and fWAR (3.5). He's also second to Ben Brown in strikeout rate (22.5%). He's been the team's best starter all year long, but there are concerns about how he'll hold up under the largest workload of his career. Case in point: he allowed 18 runs in 28 2/3 (5.65 ERA) in his final five starts in August.

Imanaga, meanwhile, leads all starters in walk rate (4.8%), batting average allowed (.202), and WHIP (0.93). He's the default choice, though he hasn't been as dominant as he was a year ago, and it feels dangerous to trust a guy whose fastball velocity has been slipping since his hamstring injury.

Horton seems like the odd-man out as a rookie, though he does lead all rotation members in ERA (2.76), ground ball rate (45.1%), and home runs allowed per nine innings (0.76). Plus, he's been unconscious in the second half, firing off a 0.86 ERA in 42.0 innings. I shouldn't need to remind you of the last time the Cubs rode the hot hand in the Wild Card Round.

There's really no wrong choice here, but that also means there's no obvious one.

For what it's worth, this is an ongoing conversation that has no strict deadline. Craig Counsell said as much to Mooney, suggesting that “You kind of circle a day when we got to make sure we’re tight on [lining up the rotation]. But now? I’ve found that whenever you make pitching plans a month in advance, you have no chance for them to be successful."

“We got at least a couple weeks before we have to take an action to prepare for this. Otherwise, there’s enough baseball, and enough happening, that I think [waiting] makes sense.”

Still, this is a topic that will dominate conversation over the next month. Assuming the Cubs can't reclaim first place in the NL Central, they will have to do battle in a best-of-three Wild Card series with one of NL's other elite teams. Lining up Imanaga, Boyd, and Horton correctly could be the difference between advancing and getting eliminated.