Tanaka was masterful in a Friday start against the Angels, throwing 7 2/3 scoreless innings while striking out nine and walking none. He has struck out at least eight and walked none in three straight starts.
The right-hander will make his 26th start of the season, the most of any Mariners starter. He has gone 7 innings or more in three of his past four starts for a 1.69 ERA in August. Iwakuma is 14-8 this season and 8-2 in his past 10 starts.