PITTSBURGH -- Understudy Jeanmar Gomez played quite the leading role Tuesday night for the Pittsburgh Pirates.
Gomez pitched five scoreless innings after being pressed into an emergency starting role when right-hander James McDonald was scratched about two hours before the start of the game with right shoulder discomfort and placed on the 15-day disabled list.
Gomez allowed two hits and two walks while striking out five as Pittsburgh snapped an 11-game losing streak against the American League West with a 4-1 victory and handed Seattle just its fourth loss in its last 11 games.
The Pirates' last win over an AL West club came June 19, 2007, at Seattle.
Pirates general manager Neal Huntington said McDonald told Pirates trainers after arriving at PNC Park that his shoulder was not feeling right. He was examined by team doctors and immediately put on the DL, though Huntington said it was too early to determine how long McDonald might be out.
Gomez (2-0) also made a spot start at Milwaukee last Wednesday and gave up three runs and four hits in four innings in place of Jonathan Sanchez, who had been designated for assignment a day earlier.
Huntington said Gomez would be a candidate to stay in the rotation. Gomez has primarily pitching in long relif this season.
Andrew McCutchen went 4 for 4, accounting for more than half the Pirates' seven hits. The center fielder is hitting .361 at home this season and .182 on the road.
Garrett Jones added a two-run homer, a liner into the right-field stands, in the eighth to push Pittsburgh's lead to 4-1. It was his fourth home run of the season.
Jason Grilli pitched a 1-2-3 ninth and is a perfect 13 of 13 in save opportunities after entering the season with just five in his 10-year career.
Aaron Harang (1-4) pitched well in defeat, giving up two runs and five hits in six innings while striking out six and allowing no walks. Harang fell to 15-7 at PNC Park, where he has more wins than any other visiting pitcher.
The Mariners were held to five hits. Pinch-hitter Raul Ibanez drove in their only run with an eighth-inning double off Jose Contreras.
Pittsburgh broke on top with two runs in the first off Harang. Starling Marte reached on an infield single and Travis Snider and McCutchen hit consecutive run-scoring doubles to center field.
NOTES: Pittsburgh recalled utility player Josh Harrison from Triple-A Indianapolis to take McDonald's roster spot, but his stay could be short as the Pirates figure to return to a 13-man pitching staff either in time for Wednesday afternoon's game against the Mariners that wraps up the two-game series or Thursday night when they open a four-game series in New York against the Mets. ... Pirates catcher Russell Martin (strained neck) was a late scratch from the lineup and is considered day to day. Michael McKenry took Martin's place behind the plate. ... Pittsburgh second baseman Neil Walker (cut right index finger) will join Double-A Altoona for a rehab assignment on Thursday and then be re-evaluated after he plays two games. Walker could be activated as soon as Sunday in New York against the Mets. ... Seattle designated hitter Kendry Morales was out of the lineup because the DH rule was not in effect in an interleague game in a National League park. ... With Seattle manager Eric Wedge forced to shuffle his lineup without a DH, third baseman Kyle Seager wound up batting third in the order for just the second time this season. ... Seattle will start Felix Hernandez (4-2, 1.60) in the series finale against Pittsburgh's A.J. Burnett (3-2, 2.57).