Rosario, a native of Nagua, Dominican Republic, originally signed with the Twins as a non-drafted free agent on November 20, 2010. In seven minor-league seasons he posted a 3.55 ERA and 1.354 WHIP in 107 appearances (55 starts).
He made two appearances for the Twins in September 2017. He got hit pretty hard in both of them, resulting in some ugly numbers: 30.86 ERA, 3.000 WHIP (eight earned runs in 2⅓ innings). Here he is recording his first major-league strikeout, of Shane Robinson of the Angels, last June:
His minor-league numbers (7.4 strikeouts, 3.7 walks per nine innings) suggest he’s “just a guy.” On the other hand, he’s lefthanded and won’t turn 24 until next May, so there’s at least a chance he’ll get better.
The Cubs’ 40-man roster now stands at 33 — that’s subtracting the eight who became free agents Thursday and adding Rosario.