One of the best rookies in the league through the first half of the season, the 22-year-old right-hander has struggled some in the second half and hasn't won since July 30. However, he has pitched well in his last two trips to the hill, but the Mariners have been blanked in each of his last two outings.
That was the case in Oakland last Saturday when Pineda allowed three runs and five hits in six innings of a 3-0 loss. He is now 9-9 on the year with a 3.74 earned run average.
"He looked really good," Mariners manager Eric Wedge said of Pineda. "I thought he threw the ball very well today. He was under control. He had good tempo. He was throwing the ball where he wanted to, mixed his pitches. I thought he threw the ball outstanding."
Pineda beat the Royals earlier in the year, holding them to a run and three hits in six innings.
Getting the call for the Royals tonight will be righty Felipe Paulino, who is 2-6 with a 4.20 ERA. Paulino did not get a decision on Monday in Oakland, but did not pitch well, as he surrendered six runs and four hits with six walks in 4 1/3 innings of his team's 11-6 win.
"He was just maybe a little rusty and was just missing. It wasn't crazy walks," Royals skipper Ned Yost said.
Paulino has never faced the Mariners.
On Friday, Miguel Olivo finished a single shy of the cycle, scored three times and drove in two runs to help Seattle to a 7-3 win. Ichiro Suzuki hit a solo homer and knocked in two runs for the Mariners, who have won three of four since a five-game skid.
Blake Beavan (4-5) gave up three runs on nine hits over 6 1/3 innings to pick up his first win since August 6.
Alex Gordon hit a solo homer and drove in two runs for the Royals, who have lost three in a row.
Jeff Francis (5-16) allowed five runs on nine hits over 3 1/3 innings to take the loss.
"I was just missing locations over and over again and when I needed to make a pitch I couldn't make it," Francis said.
Kansas City has split its six meetings with the Mariners this season. However, Seattle is 31-19 against the Royals at Safeco Field, which opened in 1999 -- its second-best winning percentage against an opponent there.