Tanaka and Iwakuma were both Tohoku Rakuten Golden Eagles (Nippon Professional Baseball) from 2007-2011. Tanaka and Iwakuma are also currently two of the best pitchers the American League has to offer.
Tanaka leads the American League in ERA (2.02) and WHIP (0.957), while Iwakuma owns a 2.66 ERA.
Monday's scheduled starter, Vidal Nuno, goes Tuesday, Tanaka will throw Wednesday and Chase Whitley will complete the three-game series with the Mariners on Thursday.
"It gives all our guys and extra day," Girardi said. "We're in a long stretch, so that can be good."
Jackson Alexander is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.