The good King or the bad King?
Will they get to see the Felix Hernandez who went a season-high eight innings in his last home start against Tampa Bay, giving up just one run on five hits with one walk and seven strikeouts?
Or will it be the King Felix who lasted just three innings on the road Saturday against those same Rays, getting tagged for six runs (five earned) on seven hits to a team that had lost eight straight games?
"He threw the ball very well and got very good results the last time out (at home)," Mariners manager Scott Servais said after Saturday's 7-3 loss. "But the key in this league is being consistent and going out there every start and giving your team a chance to win. And we were behind the eight ball after the third inning. I just want to see consistency and giving us a chance to win. And he does, too.
"Felix's stuff wasn't as good (Sunday). It was evident right from the get-go. The life on the fastball really wasn't there. It's not all about velocity. It's about locating it. And that wasn't really on either."
Hardly a ringing endorsement for a six-time All-Star and the American League's 2010 Cy Young Award winner.
King Felix is 6-5 this season with a career-worst 5.70 ERA. He has given up four or more runs in five of his past seven starts.
"I was making some good pitches and they had some hits that found some holes and there's nothing I could do about that," Hernandez said in his own defense Saturday. "I think I had pretty good stuff, they just put a lot of balls in play, just a little bit of tough luck. I was a little bit up, but I think I was making good pitches."
Maybe catcher Mike Zunino put it best, telling The Seattle Times: "There's been games where his velocity may not have been that high, but if he locates he can get away with stuff."
Opposing pitchers haven't gotten away with much against the Red Sox, who lead the American League East.
Outfielder Mookie Betts, who returned Monday from a stint on the 10-day disabled list with a left abdominal strain, leads the league with a .352 batting average and an on-base plus slugging percentage of 1.171. Teammate J.D. Martinez is second to the Los Angeles Angels' Mike Trout with 22 homers and is third in the league, behind Betts and Trout, with a 1.033 OPS.
Betts hit his first home run since coming off the disabled list Wednesday in a 5-1 victory that gave the Red Sox a sweep of Baltimore.
"I've done everything that I pretty much do, and I passed the test," said Betts, who didn't have the benefit of a minor league rehabilitation assignment. "Just trying to ride this wave."
Hernandez is 8-4 with a 4.01 ERA in 19 career starts against Boston.
The Red Sox will counter with left-hander David Price (7-4, 4.00 ERA), who is 5-0 in his past six starts overall.
Price is 3-1 with a 2.62 ERA in seven career starts against Seattle.