Shields struggled to get through six innings, but yielded only one run on six hits and three walks while striking out nine Tuesday against the Mariners to improve to 5-0 for the season. Shields gave up his major-league leading 12th homer to Brad Miller in the fifth inning, then walked the first two batters of the sixth inning. He got out unscathed and allowed just one run in becoming the first San Diego pitcher since 2007 to start the season 5-0. Shields became just the sixth pitcher in Padres' history to win his first five decisions, and it took him a season-high 115 pitches. His next start is scheduled to be Tuesday against the Cubs.