Koji Uehara Was the Best Offseason Signing for the Boston Red Sox

Where would the Boston Red Sox be without Koji Uehara? When looking at who might be viewed as the Boston Red Sox's most valuable player, no player has had a bigger impact on the team this season than Uehara.

Red Sox general manager Ben Cherington made many moves this past winter in an effort to change the Boston clubhouse and the team's culture. Most of them have worked out in the Red Sox's favor, allowing Boston to go from worst to first.

Of all the moves Cherington has made, the signing of Uehara will rank as the best one of the season and quite possibly the best bargain signing Cherington may ever make during his tenure.

Uehara hasn't just been good; he has been almost perfect, and in the process, he has saved the Red Sox from a potentially very ugly situation in their bullpen.  

Boston initially acquired Joel Hanrahan from the Pittsburgh Pirates during the winter to become the team's closer. That allowed Boston to move former closer Andrew Bailey to the eighth-inning role. The Red Sox looked like they had a deep, lockdown bullpen going into the 2013 season.

Adding Uehara during the winter was seen as a minor move, someone who might impact the Red Sox in the sixth or seventh inning and provide a veteran mentor to Junichi Tazawa. Instead, not only has Uehara assumed the closer's role, but he has also done it with such effectiveness that he has allowed the Red Sox to avoid trading any of the farm system's star prospects for another closer.

With the Red Sox winning their 81st game on the season Saturday night against the Chicago White Sox, it is time to take a moment and look at the season Uehara has had so far. Uehara has a 3-0 record with a 1.19 ERA and 15 saves. Digging deeper, the numbers are video game-like: 60.1 innings with only 29 hits and 82 strikeouts.

It is easy to make the argument that Uehara has been the best closer in the American League since taking over as the team's closer. Per Baseball-Reference, his WAR of 2.9 is the highest of all relievers in the American League.

The 38-year-old Uehara has struggled in the playoffs with an ERA of 19.29 while pitching limited innings with the Texas Rangers. It is something that bears watching if the Red Sox make the playoffs. Manager John Farrell will also have to monitor his innings the rest of the season as he approaches career highs.

Nick Cafardo of The Boston Globe reported earlier in August that Uehara had a vesting option that would go into effect for 2014. WEEI's Alex Speier confirmed the vesting option at a very reasonable $4.25 million, meaning the Red Sox should be in great shape going into the winter with the closer position under control.

As the Red Sox get ready to enter the month of September in search of the playoffs, Boston will again rely on Uehara to close games with his unique brand of enthusiasm. It is something that bodes well when thinking about October this season.