However, a rookie with a mere nine starts under his belt may be the pitcher manager Lloyd McClendon is most excited about as his team pushes toward the postseason.
James Paxton looks to continue his sensational start and help the visiting Mariners move 12 games over .500 for the first time in seven years in Wednesday's series finale with the Philadelphia Phillies.
Much has been made of Seattle's pitching staff, whose 2.94 ERA is the lowest by any team since the New York Mets recorded a 2.91 in 1988. Iwakuma lowered his ERA to 2.57 by striking out a season-high 11 over eight scoreless innings in Tuesday's 5-2 win as the Mariners (68-57) remained in a tie with Detroit for the AL's second wild card.
The Mariners, winners in 11 of 14, moved back to a season-high 11 games over .500 and haven't been 12 over the break-even mark since finishing the 2007 season 88-74.
Seattle is seeking its first playoff berth since 2001, and McClendon believes Paxton (3-0, 2.20 ERA) will have a key role down the stretch.
This will be the sixth start of the season for the 25-year-old left-hander, who is 6-0 with a 1.88 ERA and 0.93 WHIP in nine starts since making his major league debut last September. Only five pitchers since 1914 have gone undefeated with at least six wins and an ERA lower than 1.88 through their first nine games.
"I think being very talented takes a lot of the pressure off," McClendon told MLB's official website. "You can relax a lot when you've got some bullets and some weapons. Maybe that's why he's relaxed, because he throws 99 mph."
In making his third start since coming off the 60-day disabled list for a left lat strain, Paxton gave up a run and five hits over six innings in Friday's 7-2 win at Detroit. Although he only walked one, Paxton wasn't pleased with his command and said he needs to work on his mechanics before his next start.
The Phillies (55-71) counter with fellow lefty Cole Hamels (6-6, 2.44), who owns baseball's eighth-best ERA but there are more than 100 pitchers with more wins.
After permitting one run or less and pitching at least seven innings in five consecutive starts, Hamels yielded three runs and nine hits over seven in Friday's 5-3, 10-inning win at San Francisco. All the runs came on Michael Morse's fourth-inning homer - the first home run he surrendered in six games. His average of 0.54 home runs allowed per nine innings is one of the best marks in the NL.
Hamels, whose 1.60 ERA since the start of June is the third-best in baseball, lost his only outing against the Mariners three years ago.
Seattle's Logan Morrison has hit safely in 18 of 19 games and is 6 for 19 lifetime against Hamels. Kyle Seager hit his team-leading 19th homer Tuesday but is 4 for his last 28 (.143) against left-handers.
The Phillies have lost six of eight and are 5-11 against the AL - baseball's second-worst interleague record.
Chase Utley is 0 for 8 in the first two games of this series and is batting .167 (7 for 42) against lefties since July 4.