[1] Kobel was selected by the Milwaukee Brewers out of Saint Francis High School in Athol Springs, New York in the eleventh round (250th overall) of the 1971 Major League Baseball Draft.

After three seasons in their farm system, in which he went 20–24 with a 3.60 earned run average, Kobel joined the Brewers as a September call-up in 1973.

He began his major league career with a perfect inning of work in which he struck out the first two New York Yankees batters he faced and induced a weak ground ball to first base from the third.

Kobel held the Yankees scoreless on two hits through seven innings in the rain delayed second game of a doubleheader at Shea Stadium.

After surrendering a home run to Rick Dempsey to lead off the eighth, the game was called due to rain.