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Right-hander Matt Harvey begins his first full season in the majors on Wednesday when the New York Mets continue a three-game series with the San Diego Padres at Citi Field.

Big things are expected for the former seventh overall pick, who started 10 games for the Mets last season and was 3-5 with a 2.73 ERA.

"Matt Harvey, when the season was over, we said, 'Hey look, your changeup has got to be another pitch you need to use.' And all he did was come to Spring Training and worked hard to use it, and it became a very effective pitch," Mets manager Terry Collins said. "So he's made adjustments himself already."

Harvey was 2-1 this spring and pitched to a 2.96 ERA in 27 1/3 innings.

"I just think that the way he pitched in spring training, pounding the strike zone, made people swing the bats, he's going to get easier outs," Collins said. "I've seen him get deeper into games, and with that I think he's going to win a lot of games."

San Diego also has high hopes for its hurler on Wednesday, lefty Clayton Richard, who matched a career-high with 14 wins last season. However, he also gave up more hits, homers and RBIs than any NL pitcher in 2012.

New York got a well pitched game from Jon Niese in the opener on Monday and Collin Cowgill clubbed a grand slam and scored twice in the Mets' 11-2 triumph.

Niese, who also had two hits, scattered four hits and gave up just two runs over 6 2/3 innings to nail down the win in his first Opening Day assignment.

"The adrenaline was pumping, I'm not going to lie," Niese said of his first Opening Day start. "As far as the anxiety, it really wasn't much."

San Diego starter Edinson Volquez (0-1) was tagged for six runs on six hits and three walks over three-plus innings in defeat.

"The ball-strike ratio wasn't great," San Diego manager Bud Black said of Volquez. "There were a lot of two-out hits. He just couldn't make pitches at critical times."

New York was 4-3 against the Padres last season.