​Given the dearth of left-handed options the ​Cubs had available in their farm system, Joe Maddon was counting on second-year southpaw Randy Rosario to not only make the 2019 roster, but to eat up quality innings over the course of the season. 

Rosario has officially accomplished the first part of that series of goals, as he just barely snuck on to Chicago's ​Opening Day roster. 

​​After only two games as a Minnesota Twin, Rosario saw his first extended action with the Cubs in 2018, going 4-0 with a 3.66 ERA and 30 strikeouts in 46.2 innings. His inclusion on the 2019 roster might have surprised some, as he had a rough go in Spring Training, allowing eight runs and three home runs just 8.1 innings. 

Rosario features a mid-90s fastball that he pairs with a devastating wipeout slider. Both lefties and righties will have a hard time touching that when he's on. 

For the Cubs to have a chance come October, one or more of their largely unknown cast of characters in the bullpen needs to emerge as a stud. Just 25 years old, Rosario could be just that guy.