It's the third time this offseason that Rosario was claimed off waivers. Boston claimed him off waivers from Miami on Oct. 17, before designating him for assignment and trading him to the Oakland A's. The A's then DFA'd him on Nov. 30, and the Red Sox got back into it with another waiver claim on Dec. 10.
Teams are trying to get Rosario into their minor leagues, given his record there of late. He boasted a 1.99 ERA, 0.98 WHIP and 17 saves in 31 games in the minors last season. Twenty-five of those games came at the Triple-A level.
In Miami, Rosario had a 15.26 ERA and a 3.26 WHIP in 10 games (7.2 innings) at the major-league level. It's unclear if the Cubs will try and send him down immediately or let him ride the roster.