He was hurt Sunday night in a win over the Los Angeles Kings.
A first-round pick by the Oilers in 2017, Yamamoto has nine goals and 12 assists in 21 games with Edmonton this season. He also has eight goals and eight assists in 23 games with Bakersfield of the American Hockey League.
The Oilers recalled forward Markus Granlund from Bakersfield. Granlund has three goals and one assist in 32 games with Edmonton this season and six goals and nine assists in 17 games with Bakersfield.
Yamamoto's loss comes after the Oilers added Andreas Athanasiou and Tyler Ennis at the trade deadline for the stretch run. Edmonton is three points out of first place in the Pacific Division with two games in hand. The Oilers haven't made the playoffs the last two seasons.
The Associated Press contributed to this report.