Masahiro Tanaka made his 2015 debut on Monday at Yankee Stadium with his partially torn UCL and lowered velocity. The results weren't so great: 4 innings, 5 runs, 2 walks, 6 K's, 1 home run.
Tanaka told reporters at the end of Spring Training that the fastball would be down this year as he is making adjustments to his pitching style.
Lower fastball velocity might concern you. It shouldn't. What Tanaka really meant was that he will be throwing more two-seam fastballs versus four-seam fastballs. Four-seam fastballs are harder than their two-seam counterparts. Four-seam fastballs are relatively straight; two-seam fastballs (sinkers) move horizontally, vertically, or both. Here's Tanaka in 2014, according to Pitch F/X:
| Pitch | Total Pitches | Avg. Velo | Max Velo |
| 4FB | 501 | 91.1 | 95.6 |
| 2FB | 450 | 90.3 | 94.7 |
Here were the results on Monday:
| Pitch | Total Pitches | Avg. Velo | Max Velo |
| 4FB | 5 | 92.5 | 94.5 |
| 2FB | 22 | 91.1 | 92.6 |
Alarming? Hardly. In fact, the average velocity on both fastballs was up from 2014. The ratio of four-seam fastballs to two-seam fastballs was a calculated decision. I'm not sure I agree with the decision to change the ratios after such a successful 2014, but that's not my call.
Here's what to watch this season: Tanaka's fastball command within the strike zone. The Blue Jays are a good-hitting team and have a chance to lead baseball in home runs. That lineup will make you pay if you miss with your fastball, and Tanaka did miss a few times yesterday.
Tanaka thrived last season on a respectable fastball with excellent command last season. That is what complemented his split (.153 BAA, 66 K) and his slider (.134 BAA, 34 K). The off-speed pitches looked sharp yesterday, very similar to last year.
Besides health, it is the command of both fastballs that will be key to Tanaka's success in 2015. Last year he generated 11 percent swings and misses with his fastballs. In his first start it was zero percent.
