Junichi Tazawa’s effectiveness has been waning for the Red Sox

And the team may need to find a new role for him

Junichi Tazawa
Junichi Tazawa –Getty Images


Junichi Tazawa has been one of the most important pitchers on the Red Sox for years. As such, manager John Farrell has continuously trusted him in crucial situations, at times even making him the team’s closer. But Tazawa has not been right for a while now, and it’s time for Farrell and the team to reduce his burden.

Tazawa’s effectiveness dates back to 2012. He was able to toss 44 innings of sparkling relief, and by some indicators, such as ERA and FIP, it was his best season ever. The wrinkle is in the context. In 2012, he was an effective reliever, but he wasn’t exactly a trusted reliever. For starters, the team didn’t really need a trusted reliever. If you’ll recall, the 2012 season was a disaster, and most of Tazawa’s work came in the second half when the team was busy self-immolating. Tazawa saw some high leverage work in September, but for the season he entered when the margin of the game was as follows:

  • Sox ahead by four or more runs or down by two or more: 23 appearances
  • Sox ahead by three or fewer runs, tied, or down by one run: 15 appearances

After he showed he could do well during his 2012 apprenticeship, he was trusted with more of a role in 2013. At FanGraphs, there is a metric that measures the relative importance of a situation when a pitcher enters the game, called gmLI. A gmLI of 1.00 is average, with higher totals being more leveraged or important situations. In 2012, Tazawa’s gmLI was .92, which ranked ninth out of the 12 Boston relievers who threw at least 10 innings. In 2013, Tazawa had a 1.33 gmLI, which ranked third of 14 Boston relievers who tossed at least 10 innings. He was now part of the inner circle.

He proved worthy of his new role in the postseason. Win Probability Added is a story stat that captures the change in win expectancy from one plate appearance to the next. By WPA, Tazawa was the fourth-best pitcher for the Red Sox in the 2013 postseason. You can see the whole list below:

Red Sox player WPA, 2013 postseason.
Red Sox player WPA

Of course, that may be understating things. If Tazawa had not struck out Miguel Cabrera – who at the time was about to win his second-straight Most Valuable Player award and was basically the best hitter alive at that very moment – in the eighth inning of Game 3 of the American League Championship Series, there’s a good chance the Sox never see the World Series.


Tazawa has remained a key bullpen contributor ever since. From 2014 through 2015, Tazawa was the 15th-best reliever in the AL, by FIP-.  This season started out well, too. Through the end of May, everything was just peachy. Through May 27th, Tazawa had posted a miniscule 1.37 ERA and 2.18 FIP, and had struck out 25 batters in 19.2 innings. He allowed runs in just two of 21 appearances.

Then starting on May 28th, he allowed multiple runs in back-to-back appearances for just the third time in his career – and one of those three times was in his hasty call-up back in 2009. Things calmed down for a time, but then he allowed two runs in an outing on July 3rd against the Angels, and he wouldn’t pitch again in the first half. As the second half began, the team retroactively put him on the disabled list with a right shoulder impingement. His velocity had been slightly down, supporting the listed injury. When he quickly came back and his velocity was like normal for his first two appearances on July 22nd and 24th, all seemed well, especially since both outings were scoreless appearances. But his velocity has taken a sharp tick downward:

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Junichi Tazawa's velocity.
Junichi Tazawa’s velocity. —Paul Swydan

As you can see, Tazawa’s velocity is now at its lowest point in the past three seasons. Tazawa apparently knows this. From 2009-2015, Tazawa threw his four-seam fastball 62 percent of the time, which is in line with most relievers. This year, however, he has only thrown it 47.8 percent of the time, and since he returned from the DL on July 22nd, it’s just 37 percent. So, his approach has clearly been affected.

His results have as well. He is pitching in the strike zone far less frequently than he has in the past, which has led to an increase in walks. And when he comes in the zone, he is giving up harder contact, which has in turns led to a significant uptick in his home runs allowed. He’s already allowed eight home runs in 39.1 innings this season. For context, his career high HR allowed is nine in 2013, but that came in 68.1 innings pitched. Across the last two seasons, he allowed just 10 homers in 121.2 IP.


At this juncture, it seems as though Tazawa is not pitching with a full deck. Whether it’s his shoulder or some other injury we haven’t heard about, it is affecting his velocity, his approach and his results. Few pitchers have been as important to the Red Sox as Tazawa have in recent years, but it’s time for the team to push him back to middle relief duty or even place him back on the DL and give healthier pitchers like Noe Ramirez or (gasp) Joe Kelly (or a trade acquisition) a turn in the bullpen.

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