The Cubs' pitching staff right now. Guys with asterisks have minor league options:
SP - Steele, Shota, Taillon, Boyd, Rea
CL - Hodge*
SU - Pearson, Thielbar
MR - Morgan*, Merryweather
Matchup - T. Miller, Zastryzny
LR - K. Thompson
It's long been rumored the team will add a closer, so swapping that guy in for Zastryzny feels pretty easy.
Beyond that, Keegan's roster spot is the only one that feels all that tenuous. But if you replace him with someone guaranteed a roster spot you don't have anywhere for a minor leaguer to break in unless there's a cut or an injury. This staff is too mid and Iowa has too much talent to be this inflexible.