Porcello is 10-3 with a 3.57 ERA in 18 starts, but often gets discounted on a staff that includes left-handers Chris Sale and David Price, while Eduardo Rodriguez, another lefty, also posts a 10-3 record.
One can bet Red Sox manager Alex Cora doesn't overlook Porcello.
"He's been very consistent, not only on the field, but in the clubhouse," Cora said. "He shows the rest of the crew how to prepare and how to go about their business. It's good to have him in the clubhouse.
"He's a guy that will give us quality innings and find a way to give us a chance to win. He's been great."
Porcello went 22-4 with a 3.15 ERA in 2016 and won the American League Cy Young Award. He studies and is well prepared for each start.
"He's trying to find advantages and avoid disadvantages," Cora said. "He's very in-tune with the game. If you're going to beat him, you better be prepared because it's not that easy. He's a guy that does a lot. He finds a way. He's as prepared as anybody that goes out there."
Porcello went 11-17 with a 4.65 ERA in 33 starts last year.
"Since Day 1, he saw how his season went last year, a few predictable counts as far as usage, and he's made some adjustments," Cora said. "It's been great to see him successful."
Porcello has surrendered no more than two earned runs in five of his last seven starts, going 4-1 with a 3.30 ERA in that stretch. He is 8-8 with a 4.71 ERA in 22 career starts against Kansas City.
The Red Sox will be without catcher Christian Vazquez for a while. Vazquez broke his right pinkie on a head first slide into second base on a delayed steal in the seventh inning. He will be placed on the disabled list Sunday.
Sandy Leon will likely do the bulk of the catching in Vazquez's absence, while Blake Swihart, who has played at seven different positions, will back him up. Swihart has started only one game behind the plate this year.
"We've been carrying three catchers the whole time," Cora said. "But it's a big hit to us. You know how much I like the combination of both (Vazquez and Leon). It keeps them fresh and they've been doing an outstanding communicating and running the pitching staff.
"Now Blake is here, he'll play too. We're very confident that he's going to do a good job."
Junis began the season 5-3, but has lost his last seven starts. In his previous outing, Junis yielded a career-high nine runs (eight earned) on eight hits over 5 1/3 innings against Cleveland. His ERA is 5.13.
His seven straight losses are one shy of the club record held by Kyle Davies in 2011 and Jeff Suppan (2002).
Junis had a no-decision start on May 1 against the Red Sox at Fenway Park, holding them to two runs over six innings.
He is 3-7 with a 5.58 ERA in 10 home starts this season, but has lost his last five outings at Kauffman Stadium dating to May 18.
While the Red Sox lead the majors with a 61-29 record and have won five straight, the Royals are on the other end of the spectrum. They are 25-63, having dropped eight straight and 26 of 30.