Jaha, 33, was plagued by injuries to his left foot and shoulder over two previous seasons with the Milwaukee Brewers before signing a minor league contract with the A's in February.
Jaha impressed A's general manager Billy Beane and manager Art Howe, earning a spot on the team's opening day roster.
He hit .276 with a career-high 35 home runs, tying the A's record for a designated hitter. He also had 111 RBIs and a .414 on-base percentage in 142 games.
"John was an integral part to the tremendous success we had on the field this season," Beane said Tuesday. "It was important to everyone in the organization to get him back."
With a collection of raw young talent and a few veterans like Jaha and Tony Phillips, the A's finished second to the Texas Rangers in the AL West and challenged the Boston Red Sox for the wild card. It was the first time the A's were in playoff contention since 1992.
Jaha, an eight-year major league veteran, has hit .269 for his career.
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