BOSTON -- Long before closer Craig Kimbrel tweaked his left knee in pregame conditioning drills Friday, the Boston Red Sox had a need for a late-inning relief pitcher.
In the wee hours Saturday morning, they finally got one.
The Red Sox acquired side-arming right-hander Brad Ziegler from the Arizona Diamondbacks for minor league infielder Luis Alejandro Basabe and pitcher Jose Almonte, both of whom were playing at Class A Greenville.
The trade was announced at 1:42 a.m. ET, after the completion of the Diamondbacks' 6-2 loss in San Francisco.
Ziegler, an extreme ground ball pitcher thanks to a heavy sinker, has a 2.82 ERA and 18 saves in 36 appearances this season.
He told reporters he plans to join the Red Sox on Saturday.
The 36-year-old has given up 41 hits and 15 walks while striking out 27 batters in 38 1/3 innings, not nearly as dominant as last season when he posted a 1.85 ERA and allowed only 48 hits and 17 walks in 68 innings.
Ziegler is set to assume the role that has been vacant since May when right-hander Carson Smith was lost to season-ending Tommy John elbow surgery. Smith is notoriously tough on right-handed hitters, and Ziegler has likewise held righties to a .224 average over his career.
Kimbrel will undergo surgery to repair a medial meniscus tear in his left knee and is expected to miss three to six weeks, the Red Sox announced Saturday. In his absence, Koji Uehara will be the Sox's primary closer, manager John Farrell said, with Ziegler getting save opportunities when the 41-year-old Uehara is unavailable.
The Red Sox also are holding their breath over setup man Junichi Tazawa, who hasn't pitched since Sunday because of right shoulder discomfort.
To create a spot on the 40-man roster for Ziegler, the Red Sox transferred left fielder/catcher Blake Swihart to the 60-day disabled list. Swihart has been sidelined since June 5 with a badly sprained left ankle. Swihart only recently resumed light workouts in the outfield.