Moyer started the season 1-2 with a 5.29 ERA in his first eight starts, but the 41-year-old left-hander is 4-0 with a 1.60 ERA in his last eight. Last season, Moyer was an All-Star for the first time when he won a career-high 21 games.
In his last start, a 3-0 win over the Montreal Expos on Saturday, he allowed just six hits while striking out a season-high seven.
“He had great stuff,” Mariners catcher Dan Wilson said. “I don’t think it was vintage with changeup after changeup. I think he really mixed up his pitches tonight. He threw a lot of different kinds of pitches.”
Seattle has won four of six, including a 6-3 win over the Milwaukee Brewers on Thursday. The light-hitting Mariners hit three home runs in the game, including Scott Spiezio’s tiebreaking homer to lead off the eighth inning.
“Three home runs is a great thing,” said Seattle manager Bob Melvin, whose team hit three for the first time since defeating Cleveland 7-3 on May 26.
The Pirates, meanwhile, have won back-to-back games since a nine-game losing streak, including Thursday’s 5-2 win over the Anaheim Angels.
Tike Redman began the game in a 4-for-28 slump, but hit two homers during a 3-for-4 night.
Kris Benson allowed five hits, struck out eight and walked none in eight innings to win for the first time in PNC Park since beating Arizona on May 10, 2003.
Ryan Vogelsong will now try to end a drought of his own. Vogelsong is 0-6 in 11 starts since starting the season with a 6-2 win over Philadelphia on April 8.
In his last start, a 12-11 loss to the Oakland Atletics on Saturday, he gave up six runs and eight hits in four-plus innings, but didn’t receive a decision.