When the Boston Red Sox signed Hanley Ramirez to a four-year, $88 million deal with a vesting option for a fifth year, they signed a player who had been one of the game's best hitters for almost a decade. Year after year, all Hanley did was hit.

The problem was that they didn't exactly have anyplace to play him. Shortstop, his normal position, was held down by Xander Bogaerts, and Ramirez didn't really play anywhere else on the diamond.

So, Boston decided to stick him in left field, a notoriously tricky place to play, given the Green Monster in Fenway that looms over one's shoulder, making life difficult for even the most experienced of defensive outfielders.

Perhaps it was the defensive change, perhaps it was playing under the brighter lights of the Boston media, or perhaps it was just a bunch of bad luck, but the 2015 season was a nightmare for Ramirez.

He was, simply put, one of the worst hitters in the game, with a slash line of .249/.291/.426, a weighted runs created (wRC+) of 89, and a staggeringly bad fWAR of -1.8.

Among players with at least 400 plate appearances last year, his fWAR ranked 209th out of 211 MLB players. Yowza.

In the offseason, Ramirez moved to first base, a position change that seems to have helped tremendously. He is more relaxed at the plate, he has managed to stay healthy the entire season, and he's back to mashing the way he used to mash.

And on Thursday night, in a game with huge playoff implications, Ramirez delivered a walk-off blast that gave the Red Sox a much-needed victory against their bitter rivals, the New York Yankees.

When the Red Sox entered the ninth inning, they were down 5-4 and, according to FanGraphs' win expectancy chart, after Aaron Hill led off the inning with a strikeout, had just a 1.9% chance of winning the game. In fact, their odds were only at 24.8% when Ramirez hit his bomb with two on and two out, giving Ramirez 0.75 of wins probability added (WPA), a statistic that tells you how much a player has added to their team's chances of winning a game over the course of a full season.

The victory helped keep Boston on top of the American League East by two games over the Toronto Blue Jays and the Baltimore Orioles and was a crushing blow to the Yankees' flickering playoff hopes, pushing them five games back.

That dinger, by the way, came on a pitch that had some serious heat.

According to PITCHf/x records, that was the fastest pitch Ramirez has ever hit for a home run, since they started recording this data. And historically speaking, Ramirez's knock was a pretty big deal.

But back to Ramirez, who has put last season behind him in a big, big way.

He is batting .284/.356/.492 this year, with 25 homers, 100 RBI, and 76 runs scored. His walk rate has jumped from a career-low of 4.9% last season back up to 9.1%, right in line with his career levels. He is striking out more than he has historically (19.8%), but so is the rest of Major League Baseball.

In his last 30 games, Ramirez is hitting .339, with 22 runs scored, 11 homers, 7 doubles, and 38 RBI. His wRC+ of 121 is a far cry from the 89 he put up last year, and his fWAR of 1.9 is light years better than last year's -1.8. He's not great defensively at first base and never will be, but it's not a straight-up disaster, unlike his not-so-merry misadventures in left field last season.

Ramirez is hitting the ball harder this season than he has the last few, with a 36.6% hard hit rate, his highest level since 2013 with the Los Angeles Dodgers. And he's swinging at far fewer pitches out of the strike zone this season, just 67.3%, his lowest since 2012 with the Marlins and Dodgers, and much better than last year's 71.7%.

Ramirez is also swinging at fewer pitches in general, just 46.6%, down from 50.0% last year and his lowest mark since 2012. And after missing all of last September with an injury, he's reminding everyone how good he's been historically down the stretch. The Boston Globe noted that among 153 active players with 500 or more career plate appearances in September or October, Ramirez is 5th in batting average (.319), 11th in on-base percentage (.379), 12th in slugging (.529), and 9th in OPS (.918).

In his last two Septembers with the Dodgers, he was insane, hitting .370/.462/.704 in 2013 and .352/.425/.451 in 2014.

Now, Hanley is playing like the guy the Red Sox thought they were going to get when they signed him to that big four-year deal prior to the 2015 season.

And that's great news for Boston as they try to fend off three teams in the crazy, insane, American League East race.