Masahiro Tanaka is working on improving his two-seam fastball this spring.
He wants to add the pitch, which is slower than his four-seamer but has more movement, to his arsenal.
Tanaka said that he thought his four-seamer was vulnerable last season, and so he is looking to make an adjustment.
"The reason for the 88, 89, 90 [mph] is that I'm throwing two-seamers," he said through an interpreter. "The reason I'm not throwing [four-seamers] much is that a lot of the four-seamers were being hit last year during the regular season. So I'm doing this on purpose. I'm working on the two-seamers purposely."