Wakamatsu benched Figgins for failing to hustle after an errant throw from left fielder Michael Saunders -- a miscue that allowed Boston's Mike Cameron to make it to third on what should have been a lead-off double.
After the inning an altercation erupted in the Seattle dugout between Figgins and Wakamatsu that also involved infielder Jose Lopez and Mariners hitting coach Alonzo Powell. When Figgins' turn to bat came later in the game, Josh Wilson took his spot in the lineup.
The incident was just the latest in a series of intra-squad squabbles among the Mariners in a tough season that has seen them fall to a season-worst 23 games below .500.
Tensions were also high earlier this year before and after the retirement of likely future Hall of Famer Ken Griffey Jr., who some sources contend Wakamatsu forced off the team.
"It's been a rough first half, and eventually things like that are going to happen when people are frustrated," Mariners pitcher Jason Vargas told MLB.com.