Earlier this week, we discussed the many, many candidates for not-so-many spots in the Cubs’ Opening Day bullpen, focusing on the right-handed hurlers in the mix. Today, let’s tackle the lefties vying for the few open spots, and the way the team will utilize those who don’t make the cut.

It’s a different exercise than with the righties. In all likelihood, only two lefties will make the Opening Day bullpen, and if Caleb Thielbar and Hoby Milner are each healthy, they’ll be the two. Each signed with the team as free agents this winter. Neither can be optioned to the minors. A third lefty could crack the group, but two things are working against that:

The sheer volume of useful and intriguing right-handed arms they’ve collected, vying for spots; and

The fact that the team has two left-handed starters (Matthew Boyd and Shota Imanaga) slated for the Opening Day rotation, with another (Justin Steele) likely to join the mix somewhere around the All-Star break, making matchup lefties out of the pen a bit less of a pressing need.

We can approach the questions of who brings what and how each pitcher might be used (or disused) differently, then, when it comes to the lefties. Nonetheless, we can begin with the same graphic showing the arsenals and arm slots of the candidates.

vs. RHH (6).png

The six key southpaws in the bullpen mix are Thielbar, Milner, Jordan Wicks, Luke Little, Ryan Rolison, and Riley Martin. As indicated by the gold hues of the backgrounds on each of their profiles, Wicks, Little, Rolison and Martin can all be optioned to Triple-A Iowa, so tentatively, we can expect all of them to start the season there.

Wicks, the club’s first-round pick in the 2021 Draft, is also a candidate to start, though his star has dimmed over time. As is true of Ben Brown and Javier Assad from the right side, Wicks is likely to stay stretched out this spring (if he remains with the Cubs), but unlike those two, the team will be very reluctant to use Wicks as a starter in the majors. His path to helping the team is by staying capable of multi-inning stints in relief.

As high as his upside seemed to be just a year or two ago, Little now looks like the first name on the chopping block the next time the Cubs need to open a 40-man roster spot. Unless he comes to camp with his velocity restored, he’s not going to be able to help the Cubs. His fastball sat near 96 miles per hour and flirted with 100 as recently as 2024, but last year, it averaged just over 93. He needs to improve his control, too, but even at the best that his control is ever likely to be, he can’t have a meaningful impact at that number. He lowered his arm slot last season, and his size, that angle and the nastiness of his breaking ball give him real upside. To realize it, though, he has to get the juice back in his arm, and right now, that seems like a long shot.

The Cubs scooped Rolison off the waiver wire, as much because he can be optioned and stashed as because he’s a potential weapon in any kind of high-leverage situation. He has the relative cut the Cubs like on a four-seam fastball, and throws it from a high three-quarters slot, so his stuff bears a sufficient resemblance to that of Thielbar to make him a fallback plan if the aging high-slot spin master gets hurt. It’s nice to have multiple guys who offer a particular look to opposing batters, as long as one can be kept in the minors while the other is getting outs in the majors. 

Martin has a little bit of the same thing going on. He doesn’t have any big-league time yet, so we can’t precisely measure his arm angle, but it’s similar to Rolison’s. So is his arsenal, with a four-seamer and two breaking balls that work vertically, more than horizontally. The Cubs have a lot of eggs in the Milner basket right now, when it comes to getting out hitters who struggle with low-slot lefties and/or horizontal movement. That’s why Little has significant potential value, if he shows up in Mesa looking revived. Failing that, though, the team would be wise to add one more lefty whose stuff is at least roughly akin to Milner’s. That could be on a minor-league deal, but it should be someone optionable, if at all possible.

Still, this is a much more settled battle than is the one on the right side. Milner and Thielbar are a competent, veteran pair of lefties who are terrific in the clubhouse, as well as being reliable on the mound. The four other southpaws with a chance to pitch out of Craig Counsell‘s pen are all on the 40-man roster, and can all be kept in the minors. The roles are easy to divine, and the redundancies are equally clear. If the season began today, the Cubs wouldn’t be sweating about their left-handed relief corps. They have other boxes to check before Opening Day; this group could stay quite stable.

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