Jeffress, 32,was a disappointment for the Brewers in 2019 results wise as he posted a 5.02 ERA in 48 appearances while dealing with injury including a hip problem right before his release in early September. There are some indicators to suggest a bounce back in 2020. His 3.96 FIP is far better than his ERA and 63.8 left on base percentage is well below his career average.
It's fair to wonder what went from for Jeffress in 2019, he suffered from a significant 1.4 MPH drop on his sinker velocity which allowed hitters to hit .291 against the pitch compared to a .215 mark from the year before. His split-fingered fastball was also disastrous for him as hitters hit .400 off the pitch in a much smaller sample size than the year before where hitters hit .188 off the pitch.
Overall for his career he has posted a 3.16 ERA in 392 career games including one start. He has pitched 401 total innings striking out 370 while walking 163. He has pitched for four big league teams, but has had the most success for the Brewers posting a 2.66 ERA in 301 appearances split across seven seasons.
It is extremely unlikely that Jeffress will return to his 2018 form where he was all All-Star posting an incredible 1.29 ERA in 76.2 innings for the Brewers bullpen. But he has shown the ability to be a solid big league reliever and if he can get his velocity back up and some of the bad luck disappears then he can definitely be an asset to the Cubs bullpen in 2020..