SEATTLE -- Justin Smoak hit a three-run homer in the fifth inning and the Seattle Mariners beat Kansas City 4-0 on Tuesday night, putting the Royals' post-season hopes in serious jeopardy.
Mariners rookie left-hander James Paxton (3-0), making just his fourth major league start, worked a career-high seven innings, allowing four hits, walking none and striking out a career-high 10.
The playoff picture looks as bleak as it can be for the Royals (83-74). They are four games behind Cleveland for the second wild-card berth with five games to play.
The Royals' three competitors for the two wild-card spots -- Tampa Bay, Texas and Cleveland -- all won Tuesday. The Royals need to win every game and have both the Indians and Rangers completely collapse.
It was the 13th shutout for the Mariners and the ninth time the Royals have been shut out.
Seattle touched Bruce Chen (8-4) for a run in the first when Brad Miller reached on an infield single followed by Abraham Almonte's single to centre. Almonte has reached base in all his 18 games to start his career, 16 with a hit.
With one out, Kendrys Morales singled to left, driving in Miller.
Chen worked five innings, allowing seven hits and four runs. He walked three and struck out five.
The Royals could not respond against Paxton. They put together two singles in the first inning but a double play eased him out of trouble. He didn't allow more than one baserunner in any inning after that and at one point he retired 12 straight.
The Mariners blew the game open in the fifth with three runs -- all with two outs. Morales, who had three hits, doubled to deep centre. Franklin Gutierrez walked and Smoak hit a 0-2 fastball over the wall in left field.
Smoak has 19 home runs but it was just his second right-handed. The other was Sunday against the Los Angeles Angels.
NOTES: Mariners LHP Danny Hultzen, the second player taken in the 2011 draft, has a problem with his left shoulder and will see Dr. James Andrews on Monday. "Ed (team doctor Ed Khalfayan) saw him and, quite frankly, doesn't like what he sees," GM Jack Zduriencik said. "He saw some damage that he was unhappy with. It's in the shoulder but not in the rotator cuff, more tendon area, labrum." . The club confirmed Zduriencik will return in 2014. . The Royals need one more win to match their win total from 1993 (84-78). ... Eric Hosmer of the Royals had two hits, his ninth multi-hit game in September. He leads the AL with 59.