Craig Brooks has a pattern of struggling with his control after a promotion. It's likely a mental thing, thinking that you have to be extra precise because the hitters are better at this level so you start nibbling instead of continuing to do what got you there and trusting your stuff. In 2016, his first full season in pro ball, Brooks was still refining his command. He was dominating Low-A with a 1.39 ERA while striking out 30.7% but walking 14.6%. After his promotion, he posted a 8.25 ERA with a 22.1% K-rate and a 16.4% BB-rate. His BAA jumped 100 points from .196 to .296. In 2017, he once again starts off dominating, this time in Myrtle Beach (where had finished the year prior) with a 0.44 ERA, a 39.5% K-rate, 7.9% BB-rate and a .134 BAA. After another mid-season promotion to AA, he had an ERA of 4.46, a 31.7% K-rate and a 15.9% BB-rate. His BAA, while still good, jumped to .201. This year, starting off in AA, he posted a 3.00 ERA, a 35.0% K-rate, a 7.7% BB-rate and a .181 BAA. After his promotion to AAA Iowa, his ERA ballooned to 4.73 (it was 7.36 2 weeks ago) with a K-rate of just 18.6% and a BB-rate of 27.1%. His BAA has actually remained good at .174. Assuming the pattern continues and Brooks starts 2019 dominating AAA (or at least markedly improving), the Cubs would have 4 intriguing, home grown relief arms ready to ride the shuttle or break with the team in Norwood (25), Maples (26), Mekkes (24) and Brooks (26). (Ages are as of opening day 2019). That would be a 1st during the Theo & Jed era and a sign of the Cubs improving pitching depth. The only pitcher from that group not currently on the 40-man roster is Mekkes. Mekkes isn't eligible for the rule 5 draft this winter so they can afford to keep him off the 40-man roster this off season which may be the reason why he hasn't been added already. It will be interesting to see if he is among the September call ups. He's certainly deserving, but that's not always the only consideration. Add in this year's successful acquisitions of Justin Hancock (Szczur trade), Randy Rosario (waivers) and Luke Farrell (waivers), all of whom will have options next season, and the relief depth looks even stronger. If none of them break with the team, that's a nice 7-man AAA bullpen right there (though Farrell would likely be in the rotation), albeit with just one lefty in the group.