Willson Contreras returned to the Boston Red Sox lineup Sunday, activated from the 10-day injured list and slated to bat cleanup against the Kansas City Royals. The 34-year-old first baseman went on the IL on Aug. 31 with a strained left hamstring.

Contreras leads the Red Sox with a career-best 26 homers and 79 RBIs while entering with a .274 average. He played two rehab games for Double-A Portland, going 2-for-7 with two RBIs.

"He's an important piece to the offense. Kind of like the aircraft carrier there in the middle," Boston interim manager Chad Tracy told reporters Friday. "When he's right, obviously inserting that bat is important."

Infielder Anthony Seigler was put on the 10-day IL with right wrist inflammation. He got hurt during a swing in Saturday's 5-1 win over the Royals. ESPN News Services reported from BOSTON, with The Associated Press contributing.