After justifying his spot in the San Diego Padres' rotation, Drew Pomeranz is out to prove his first real hiccup was an aberration.

Pomeranz hopes to end the Padres' struggles in the opener of an NL West series against the visiting Colorado Rockies on Friday night.

San Diego (21-34) pounded out a season-high 20 hits Thursday but blew a 10-run lead to fall on the wrong end of a 16-13 slugfest against Seattle. The loss was the ninth in 11 games for the Padres, who fell to 11-16 at home.

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However, San Diego won two of three in each of this season's first two series against Colorado (24-29). The Padres have won 14 of the last 18 of this series at home.

Manager Andy Green took a chance on Pomeranz (4-5, 2.48 ERA) at the end of a shaky spring performance, naming him the fifth starter even though most believed he'd work out of the bullpen.

The 2010 first-round draft pick made his skipper look like a genius in his first nine starts, leading the Padres in wins and strikeouts (60). His 1.70 ERA through his first nine career outings was second to Clayton Kershaw of the Los Angeles Dodgers and only former San Diego Cy Young Award winners Randy Jones and Jake Peavy.

However, the left-hander suffered his first major setback in Sunday's 6-3 loss at Arizona. Pomeranz struck out nine but gave up six runs on five hits in five innings, and he walked four for the second straight start. He settled down after a five-run second inning and didn't allow a hit to the final 13 batters he faced.

"I just had a better mix," Pomeranz told MLB's official website of his approach from the third inning on. "I didn't mix from the beginning, I kind of got a little predictable. You've got to be able to read that sooner and start mixing pitches."

While Pomeranz has taken the loss in two of his three starts since his last victory May 11, Colorado's Chris Rusin has two losses and a no-decision in his last three.

After showing improvement by giving up two runs over 10 2/3 innings in two outings - including one relief appearance - Rusin (1-3, 4.75) took a step back in Sunday's 8-3 loss to San Francisco.

The Giants pounded the left-hander for 11 hits and six runs in five innings. Rusin gave up his first homer of the year and issued four walks, though one was intentional.

"I didn't make pitches to get out of the jams," Rusin said.

After throwing five one-hit innings in his first start April 30, Rusin has given up 40 hits and 19 runs in 21 1/3 innings over his last four starts with an 8.14 ERA.

Rusin opened the season out of the bullpen and was hit hard in an April 8 outing against San Diego, giving up three hits and three runs to move his career ERA to 4.12 versus the Padres.

He held a 2.95 mark in three previous starts against them, which included a five-hitter in a 5-0 victory Aug. 16.

In limited at-bats against him, Jon Jay (5 for 6, two doubles), Matt Kemp (3 for 6, home run), Derek Norris (4 for 8, double), Yangervis Solarte (2 for 4, double) and Melvin Upton Jr. (3 for 6, two doubles) have hit Rusin well.

Jay went 4 for 6 with a double in Wednesday's 14-6 win over Seattle and followed with a 5-for-6 performance on Thursday - raising his batting average above .300 for the first time since April 12.