Chicago Cubs: Randy Rosario was a pleasant surprise out of the bullpen

I’m sure entering the 2018 campaign that very few Chicago Cubs fans were familiar with the name Randy Rosario. That all changed, as by season’s end Rosario had established himself as a reliable piece in the Cubs bullpen.

When the Chicago Cubs acquired Randy Rosario via waivers last winter it wasn’t a move that made headlines by any stretch. In fact, most people probably didn’t think anything of it. In his career with the Minnesota Twins organization, he had hardly sniffed the big leagues, appearing in just two games in 2017.

Rosario began his career with the Cubs playing in Iowa, but his dominant performance was hard to ignore. At Triple-A, Rosario posted an ERA of 0.79 over the course of 22 2/3 innings in 15 appearances.

Injuries to the big league club ultimately opened the door for Rosario and he made his debut with the Cubs on May 19 against the Cincinnati Reds. He pitched two shutout innings of relief, striking out two batters and walking one.

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The left-handed reliever got off to a hot start with the Cubs. He didn’t allow a run over his first five appearances – spanning 7 2/3 innings. Over that span he earned two wins while striking out six batters and walking four.

In his first season with the Cubs, Rosario appeared in 44 games and gave the Cubs 46 2/3 innings of relief. The rookie posted a 3.66 ERA to go along with 30 strikeouts and 22 walks on the year.

Rosario fills a void for Maddon

Where Rosario really made his mark was in his matchups against left-handed batters. In those matchups, Rosario pitched 20 2/3 innings, the second most of any Cubs left-handed reliever. He posted a 2.18 ERA surrendering just five total runs.

An area Rosario really shined at was keeping runners off the base paths. He posted the lowest WHIP among Cubs left-handed relievers with a 1.060 by allowing just 12 hits and 10 walks.

Rosario really gained Joe Maddon’s trust in these situations as the season went on. Initially, there weren’t a lot of options aside from Justin Wilson and Brian Duensing. Not to mention the Cubs were counting on Mike Montgomery to come out of the bullpen but he was moved into the starting rotation early in the year in lieu of the Yu Darvish injury.

We saw just how much Maddon trusted Rosario in lefty-lefty matchups when he called for Rosario to face Christian Yelich in game 163. With the Cubs trailing 2-1 in the eighth inning with runners on first and third Rosario came in for one batter and struck out the eventual NL MVP. Talk about showing confidence in the young 24-year-old.

Even though Rosario struck out Yelich in a big spot he hadn’t come up with a lot of strikeouts against lefties throughout the season. On the year he only tallied 18 strikeouts in those matchups, coming out to a 7.9 strikeout per nine ratio.

If Rosario were to develop a strikeout pitch he could really take a big step forward in 2019. He will more than likely be relied on heavily again next season, especially if the Cubs fail to bring back Wilson, who is a free agent.