Eddie Rosario Fixed His Biggest Problem

At the end of April, Eddie Rosario was hitting .268/.294/.366, a line well below his career averages, and one he couldn't afford in his third major league season. At 25 years old and with just one minor league option left on his contract, he was running out of time to prove he could be a multidimensional and productive hitter.

In his first two years, Rosario showed little interest in watching a bad pitch go by: between 2015 and 2016, only Adam Jones came to bat as often as Rosario and swung at more pitches out of the zone. Making matters worse was his difficulties with making contact. His strikeout and especially walk rates were both subpar, meaning in order to post a good line, he had to do exceptionally well when he made contact. While he possesses adequate speed and power, neither tool has ever been so strong that he can rely on them. As a result, he couldn't crack a .300 on-base percentage in either major league stint despite a relatively high (but repeatable) BABIP, and he was a below-average hitter overall.

After two seasons of nearly identical play, there were significant doubts that Rosario would change his profile and have a future as a starter in the majors. Those doubts grew stronger a month into 2017. Fortunately, with no apparent replacement on the roster or at AAA, he kept getting playing time.

The first sign Eddie Rosario was a different player was there in his dismal April. Only once since his debut had he finished a month with a strikeout rate lower than 20 percent; in April, he struck out in 18.6 percent of his plate appearances, a mark he perfectly matched the next month. A more important trend emerged in May as well.

Below is the important graph. It shows Rosario's rolling swing rate on pitches both inside and outside of the zone since his debut. It's pretty easy to tell when he changed his approach.

The spot at which the blue line plummets starts midway through May of this year. The result is that since May 16, Rosario has struck out at a practically league average rate (21.9 percent) and walked more than he ever has before (7.1 percent). He has already matched his rookie season walk total of 15 in almost 50 fewer games.

Not only that: for the year, his swing rate on strikes for the season has remained stable but slightly increased, meaning he hasn't become an entirely passive hitter. With his time running thin, Rosario became much more adept at recognizing pitches without changing his solid batted-ball tendencies, and he's hit extraordinarily well. Plus, he's producing in multiple ways, as shown in his two most impressive games of the year: on June 13, Rosario had his first multi-home run game, slugging three against the Mariners; and on July 1, he went 5-for-5 against the Royals, the third game of his career in which he's reached base in each of three or more plate appearances. Again since May 16, he has hit .297/.349/.507, making him 25 percent better at the plate than the average major leaguer over that time. He is now one of the most dangerous players in the Minnesota lineup.

Rosario still has a significant platoon difference, but it's not so dramatic that it should keep him out of the lineup against lefties. If he can keep up this patience, he should be one of the Twins' best hitters and fully live up to the expectations he faced as a prospect.