Justin Steele and Shelby Miller continue Triple-A Iowa rehab as Cubs' bullpen depth thins

Justin Steele and Shelby Miller are both continuing rehab assignments at Triple-A Iowa, MLB.com's Manny Randhawa reported, as the Chicago Cubs navigate a stretch run with a bullpen that has been absorbing losses at an uncomfortable rate.

What happened

Neither Steele nor Miller has rejoined the Cubs' active roster. Both remain at Iowa on rehab assignments, per Randhawa's report, with no return date attached to either name. The Cubs have not announced a timeline for activating either pitcher.

Under general league mechanics, pitchers on rehab assignments have up to 30 days before a club must activate them or make another roster decision. Where Steele and Miller fall within that window has not been reported.

Why it matters

The Cubs are trying to hold a Wild Card position in the final weeks of the regular season, and the pitching staff around them has been thinning in ways that make every healthy arm feel load-bearing. Phil Maton, a Cubs reliever, will undergo right knee surgery this week for a partial patellar tendon tear, effectively ending his 2026 season, as Posterior Wire reported earlier this week. Ben Brown, the Cubs right-hander dealing with a neck stress reaction, is not expected to return for the remainder of the season and will remain on the 60-day IL, per a report from earlier this month.

That is two relievers already removed from the equation before the calendar reaches mid-September. Steele and Miller, still working through their respective recoveries in Iowa, represent potential reinforcements — but "potential" is doing real work in that sentence until the Cubs announce otherwise.

Steele, when healthy, has been one of the more reliable arms in the Cubs' rotation. His absence has been felt in the kind of quiet, structural way that only becomes loud when you look at who is being asked to fill the innings. Miller's role and the nature of his injury have not been detailed in the report, but his presence at Iowa alongside Steele signals the Cubs are at least monitoring two pitchers who could factor into the roster before the season ends.

The September roster expansion — which allows clubs to carry 28 players through the end of the regular season under general league rules — gives Chicago some flexibility to add arms without immediately displacing position players. Whether Steele or Miller returns in time to use that window is, for now, an open question.

The numbers

The Cubs enter Friday at 81-66 (.551), sitting second in the NL Central, 10 games back in the division. Their Wild Card standing is more immediately relevant: they rank second among Wild Card contenders, sitting +2.5 relative to the cut line. The cushion is real but not comfortable, particularly against the backdrop of a four-game losing streak heading into the weekend.

The upcoming schedule offers some context for why the pitching picture matters right now. Friday brings Shota Imanaga to the mound against the Pittsburgh Pirates at Wrigley Field, with Wilber Dotel starting for Pittsburgh. Saturday, Clay Holmes faces Paul Skenes in what figures to be the marquee pitching matchup of the series. Sunday, Matthew Boyd draws the start against Bubba Chandler.

Three games against Pittsburgh, at home, with the Wild Card margin sitting at +2.5. The rotation looks set for the weekend. The question is what happens in the innings between the starters and the final out.

Where the club stands

At 81-66, the Cubs are a winning team in a tight race. Second in the NL Central, second in the Wild Card standings, and riding a four-game skid that has a way of making every roster decision feel more consequential than it might in July.

The offense has not been the problem. Pete Crow-Armstrong, who hit his 40th home run of the season earlier this month and now sits at 41 home runs and 36 stolen bases per Posterior Wire's reporting, has been one of the best players in the National League this year and is drawing NL MVP consideration. That kind of production at the top of the lineup buys a pitching staff some margin for error.

But margin for error is not the same as margin for attrition. Ian Happ was scratched from the lineup with left knee discomfort earlier this week, adding another name to the list of Cubs who have spent time in the training room this month. The Cubs have been managing a roster that keeps requiring management.

Against that backdrop, the Steele and Miller rehab assignments are less a footnote and more a thread the Cubs are hoping to pull. Two pitchers working their way back at Iowa, with the Wild Card race entering its most consequential stretch, is the kind of situation where "continuing rehab" is the most important two-word phrase in the transaction wire.

What we don't know yet

The nature of Steele's injury and the specific diagnosis behind Miller's absence have not been detailed in Randhawa's report. No timetable has been reported for either pitcher. It is not known how many days each has remaining on his rehab assignment, nor whether either has encountered setbacks in Iowa.

Whether either pitcher would return to a starting role, a bullpen role, or some hybrid capacity has also not been addressed. Given the state of the Cubs' relief corps — with Maton's season over and Brown unavailable — the bullpen would seem to have the more pressing need, but roster construction decisions belong to the Cubs' front office, not to inference.

What to watch

The most direct question for Cubs fans this weekend is straightforward: when do Steele and Miller come back, and in what capacity? Randhawa's report establishes that both are still in Iowa and still rehabbing — the next development to watch is any Cubs announcement about activation or a change in assignment status.

Beyond the two pitchers, the weekend series against Pittsburgh at Wrigley Field carries genuine stakes. With the Cubs at +2.5 relative to the Wild Card cut line and a four-game losing streak in tow, the three-game set offers an opportunity to stabilize — or to make the bullpen situation feel even more urgent. Holmes versus Skenes on Saturday is the kind of pitching matchup that tends to draw attention regardless of standings, but the standings are very much present.

The Cubs' ability to hold their Wild Card position through the final weeks of the season may depend, at least in part, on whether Steele and Miller can make it back to Wrigley before the roster freezes. For now, they are in Iowa, continuing to work. The Cubs are waiting, and so is everyone else.