O'Sullivan helped to anchor the league's best pitching staff, striking out 55 and allowing just two homers in his first professional season.
Pettit, this year's 19th-round pick, ranks among the top five in the league in batting average, on-base percentage, slugging percentage, doubles, RBIs and extra-base knocks. His .567 slugging mark is nearly 100 points over the second-highest percentage on the team.
Starters Trevor Bell and Herndon and reliever Felipe Arredondo earned spots on the honorable mention list. Arredondo, who leads the league with 26 appearances and is second with 10 saves, has 54 strikeouts in just 40 innings of work.
Herndon, in addition to a league-best 2.13 ERA, opponents hit just .233 against him with nine walks in 63.1 innings of work. Bell, who is second in the league with 76.1 innings pitched, also ranks in the top 10 with a 3.66 ERA.
At the plate, outfielder Peter Bourjos and shortstop Ryan Mount were recognized. Bourjos has a team-best seven triples and 12 stolen bases while playing stellar defense in center field during his first professional season. Mount leads the club with nine homers and has scored 52 runs while leading off for the Owlz.
For Kotchman, the Manager of the Year honors are the second in three years.