Tatsuya Imai — Career

Tatsuya Imai's NPB career with the Seibu Lions spanned seven seasons (2018–2025). Drafted first overall from Sakushin Gakuin High School in Tochigi Prefecture, he missed his first two professional seasons due to right shoulder injuries before beginning to emerge in 2021. In 2022, he went 13 wins with a 2.91 ERA and established himself as a key part of the Seibu rotation. He continued to refine his craft through 2023 (10 wins, 2.70 ERA) and was considered for Japan's WBC roster. His 2024 breakout — including the NPB strikeout title with 187 K — confirmed what scouts had long suspected: his mid-90s fastball and diving forkball generate elite swing-and-miss rates. The 2025 campaign was his finest, producing a career-best 1.92 ERA across a full 25-start workload, with peripherals (FIP under 2.40, WHIP under 1.00, K/9 above 11) that validated the surface ERA. Seven years of NPB experience and development — including refining his slider into a reliable third pitch and deepening his pitch sequencing — set the stage for his MLB leap with the Astros at age 27, a prime window for a power pitcher. For sabermetric readers: Imai's NPB FIP-ERA gap (FIP near 2.40 vs ERA 1.92 in 2025) suggests his run prevention was modestly aided by sequencing and defense, but the underlying skills — strikeout rate, contact suppression, pitch-mix grade — were genuinely elite. His MLB projection systems (Steamer, ZiPS) coming into 2026 generally pegged him as a 3.50–4.20 ERA mid-rotation arm with high strikeout upside, and his early-season K/9 (~13.5) is exceeding even the optimistic projections. The walk-rate adjustment is the single biggest swing factor for whether he lands closer to the optimistic or pessimistic end of those projections by season's end.