From the Cubs site:
Over the first 16 games of this season, Chicago's rotation went 12-3 with a 2.55 ERA, which was the second-lowest mark in the Majors. In the next 22 games, leading up to Saturday's twin bill, the rotation had gone a collective 6-8 with a 5.15 ERA, and 2-8 with a 6.48 ERA without Darvish's stellar starts.
Lester has an 8.55 ERA in four starts during that stretch, while Alec Mills has a 7.66 ERA in five outings. The Cubs need them to get back on track, while the team considers its options the next time the need for a No. 5 comes around (Thursday vs. the Reds).
“I'm here to help the team in whatever spot they need me, you know?” Alzolay said. “For this year, it doesn't matter if it's out of the bullpen or a spot-start like I've been doing lately. Like I said, that's my mindset right now.”
Alzolay remains the top choice -- with righty Tyson Miller also an option after being recalled between games Saturday, as the club
designated Steven Souza Jr. for assignment. Then, there is the question of whether the Cubs would consider promoting lefty Brailyn Marquez, their
No. 1 prospect. It might not be out of the question before the season ends.
This last bit is just a muse by the writer but it is not stupid. Marquez has ace quality stuff and the current environment is ideal to see how that plays against the top tier.