#2: Brandon Hughes
Brandon Hughes, the Cubs' main lefty to open the season, could be bound for Chicago before the postseason begins. He didn't get much runway with the team to open the season following a lingering issue in his left knee that eventually led him to undergo surgical debridement earlier this year. Only recently did Hughes take the mound for his rehab stint in Iowa, putting a return in the waning months of the season, and potentially the playoffs, into the realm of possibility.
There's no telling if Hughes will be back in peak form upon his return, but if he was, he'd be a strong candidate to make the cut for October. The southpaw broke out with the Cubs in his debut last year, posting a 3.12 ERA across 57 2/3 innings albeit with a much less impressive 4.64 FIP that suggested some good luck. There were reasons to believe in him long-term, though, including his 91st percentile whiff rate and respectable 3.86 expected ERA.
The Cubs still don't have an established lefty this year, often defaulting to Mark Leiter Jr. to take on any southpaws. Hughes would fix that problem and could easily justify a spot in the playoffs over Hayden Wesneski or Keegan Thompson should they continue to struggle. The main hurdle for him to clear is getting back in form after surgery.