On April 1, 2007, Ellison was traded to the Seattle Mariners for Travis Blackley, where he served much of the 2007 season as a fourth outfielder.

Ellison was a key part of an altercation between the Oakland Athletics and his Seattle Mariners that started after A's pitcher Joe Blanton collided with Mariners outfielder Ichiro Suzuki while retrieving a ball that had gotten away from the A's catcher.
Ellison responded by charging Blanton, and a bench clearing scuffle ensued.
In spite of this, Ellison was not ejected from the game, and went on to record the first 4-hit game of his major league career.
In 2009, Ellison and Blanton became teammates on the Philadelphia Phillies.

On August 3, 2007, the Seattle Mariners designated Ellison for assignment, making room on their 25-man roster for rookie outfielder Adam Jones to be called up from their Triple-A affiliate, the Tacoma Rainiers.
On April 1, 2007, Ellison was traded to the Seattle Mariners for Travis Blackley, where he served much of the 2007 season as a fourth outfielder.
Ellison was a key part of an altercation between the Oakland Athletics and his Seattle Mariners that started after A's pitcher Joe Blanton collided with Mariners outfielder Ichiro Suzuki while retrieving a ball that had gotten away from the A's catcher. Ellison responded by charging Blanton, and a bench clearing scuffle ensued. In spite of this, Ellison was not ejected from the game, and went on to record the first 4-hit game of his major league career. In 2009, Ellison and Blanton became teammates on the Philadelphia Phillies.
On August 3, 2007, the Seattle Mariners designated Ellison for assignment, making room on their 25-man roster for rookie outfielder Adam Jones to be called up from their Triple-A affiliate, the Tacoma Rainiers.
Jason Ellison