Overcoming a slump to achieve a career high

This season was his ninth as a professional Saitama Seibu Lions Tatsuya Imai pitcher. He opened the season pitcher for the second consecutive year and led the starting rotation from there, appearing in 24 games. He eventually finished the season with his first ERA single-season record and reached double-digits win for the third consecutive year. He had the best season of his career, recording 5 complete game and 3 shutout game, both personal highs.

Particularly impressive was a game against Yokohama DeNA on June 17, when he set a new team record of 17 strike out in a single game. Even so, Imai pitcher did not pitch as well as he would have liked in all of his appearances during the season, and in July he was in a slump, scoring five ERA runs in the month. One of the keys to getting out of this slump was learning a new pitch in the middle of the season.

Introduced a new pitch, sinker in August

The table above shows the pitch ratio of different pitches to left-handed right-handed hitter this season divided into two periods: before July and after August. What I would like to pay attention to are the two pitches of fork and sinker, and the percentage of fork has decreased since August, and new balls and sinker have appeared instead. Saitama Seibu has a sinker user named Ryota Itokawa pitcher, and in the process of learning the new ball, it seems that he received advice from the right-hander of this same year. He also expressed his gratitude for getting rid of the illness he fell into in July and regaining his form in August, saying that it was thanks to pitcher Itokawa. sinker is the same drop breaking ball as the original fork, and it is also used a lot for left-handed hitter, but it is characteristic that the ratio of right-handed hitter to is relatively high at 7.6%.

New tempo changes added mid-season

Next, let's look at the effect of this new pitch, which he began throwing in August. The average speed of his five existing pitches this season is over 150 km/h for fastball, around 138 km/h for slider, change-up, and fork, and about 125 km/h for the curveball he occasionally throws, splitting the pitches into three speed ranges. On the other hand, sinker doesn't fall into any of these three categories, averaging 131.5 km/h, differentiating it from change-up and fork, which are also dropping breaking ball. By adding a new pitch in a new speed range mid-season, hitter likely found the difference in speed more troublesome than the numbers suggest.

He can toy with opponents regardless of whether they are left-handed or right-handed hitter

sinker The strikeout rate of pitch to right-handed hitter was the highest among all pitches against both left and right, especially against right-handed hitter at 35.7%. Before July, was constructed almost exclusively with fastball and slider, so there were some surprising strikeouts against sinker, which has a different trajectory and velocity. Against left-handed hitter, the ball not only took strikeouts, but also functioned as a ball that made the batter hit a ground ball, with a 62.5% ground ball rate, and was powerful at 18 At Bat 1 hit 10 strike out. Against left-handed hitter, Avg was good enough for .194 before July, but since August it has been even better, at .146, and we think sinker helped a lot with this.

Record Avg

pitcher Imai's Avg.176 this season is the first in the NPB to reach the innings pitched of regulation over the past 10 years. If he had been slow to recover from the poor performance in July introduced at the beginning, he probably wouldn't have achieved such results. It can be said that the bold attempt to acquire a new ball in the middle of the season, which could upset the balance of the pitch if one wrong move, led to record good results.

This season, which was welcomed by new coach Fumiya Nishiguchi, finished in 5th place and missed out on entering the A class, Saitama Seibu. It was a tough battle for the team, but pitcher Imai, who continued to stand at the mound as an ace, had an outstanding presence. Now that the regular season is over, all eyes are on pitcher Imai's future future, but who knows yet where he will be on the stage next. However, one thing is certain: no matter where it is, he will continue to challenge without fear of change and captivate fans with his pitching.

*All numbers in the text and table are as of the end of the 2025 season.

Moon/Data Stadium