Kansas City is in need of a boost heading into the All-Star break.

The reigning World Series champion Royals have dropped five of six entering Thursday's opener of their four-game series with the Seattle Mariners in Kansas City, which will bring both teams into the break.

Kansas City suffered its fourth straight loss Wednesday night while stumbling through a three-game sweep by Toronto, which concluded with a 4-2 defeat.

More from FoxSports

The Royals (43-41) haven't been as dominant since ending a 30-year title drought last year, but they're only a hot streak from contending in the American League Central.

"We're an aggressive team when we're swinging the bats well," Kansas City manager Ned Yost said. "Right now, we're just not making any hard contact."

Seattle, meanwhile, had won five of eight entering Wednesday's series finale at Houston, which it lost 9-8 after starter Wade LeBlanc gave up five runs in 3 1/3 innings.

The Mariners (43-42) took two of three when the teams first met this year on April 29-May 1, blanking Kansas City in the first two games. Last season, the Royals won four of six against the Mariners.

Two 27-year-old southpaws toe the rubber Thursday as Seattle's James Paxton (2-3, 4.24 ERA) counters Kansas City's Danny Duffy (4-1, 3.11).

Paxton is making his eighth start in place of ace Felix Hernandez, who landed on the disabled list June 1 with with a strained right calf.

He is 2-3 with a 4.24 ERA in place of Hernandez, who threw a 45-pitch, three inning simulated game Wednesday and said he is ready to begin a minor league rehab assignment.

"That was pretty good, to get back out there and face some hitters," Hernandez told MLB.com. "That last inning was 100 percent. I picked up the intensity and it was way better. It felt pretty good. I'm happy."

In his last outing, Paxton surrendered four runs (three earned), nine hits and two walks with two strikeouts in 5 2/3 innings of Saturday's victory over Baltimore.

Paxton has experienced smooth sailing against the Royals historically, going 1-0 with a 2.16 ERA in two starts against the defending champs.

One of his best starts came against Kansas City in 2013, when he struck out a career-high 10 batters while holding the Royals scoreless on four hits and no walks in seven innings.

Eric Hosmer is the only Kansas City batter with more than one hit off Paxton, going 2-for-4 against him.

Duffy is looking to make it three straight starts of at least eight innings after allowing just four runs while striking out 16 in his last 16 2/3 innings entering Wednesday.

On Saturday, Duffy limited Philadelphia to two runs and seven hits in a personal-best 8 2/3 innings, fanning eight for the third consecutive start. He also didn't walk a batter for the second straight outing.

In his last six starts, Duffy has had his punch-out pitch working, striking out eight or more in five of those outings -- including a career-high 10 on June 11 at the Chicago White Sox.

Duffy is 0-1 with a 1.69 ERA in five career appearances (three starts) against the Mariners. Robinson Cano has given him fits, going 4-for-11 (.364) with a homer and four RBIs.

Chris Ianetta has two hits against Duffy, going 2-for-6 with a homer and two RBIs, and Kyle Seager is 3-for-8.