BOSTON -- Several hours after Red Sox closer Craig Kimbrel revealed discomfort in his left knee, president of baseball operations Dave Dombrowski made a significant move to fortify the bullpen, adding righty reliever Brad Ziegler in a trade with the D-backs.
Kimbrel was placed on the 15-day DL on Saturday and the Red Sox announced the closer will miss the three-six weeks and undergo surgery to repair a medial meniscus tear so Ziegler might be in line to close games for the club.
To acquire a pitcher who has 81 career saves, including 18 this season, the Red Sox parted with two Minor League players: Right-hander Jose Almonte and infielder Luis Alejandro Basabe.
It was Dombrowski's third trade in a span of about 32 hours, this one getting announced at approximately 1:45 a.m. ET on Saturday morning. The Red Sox are 47-38, and two games behind the Orioles in the American League East.
"From a baseball standpoint, you have a team that's just a couple of games out of first, and there's a lot of opportunity there," Ziegler told MLB.com's Steve Gilbert. "I think that's probably why they [made] some adjustments now so we can maybe make up some games before the end of July."
• Kimbrel could miss ASG with knee discomfort
Regardless of Kimbrel's health, the Red Sox had been looking for more bullpen depth. They started talking with the D-backs about Ziegler a couple of days ago, according to Arizona general manager Dave Stewart.
With righty setup man Junichi Tazawa also dealing with right shoulder soreness and Carson Smith out for the season following Tommy John surgery, Dombrowski couldn't afford to wait around.
The 36-year-old Ziegler was was 2-3 with a 2.82 ERA in 36 relief appearances for Arizona this season, converting all but two of his save opportunities. The right-hander also has 27 strikeouts and only one home run allowed over 38 1/3 innings.

Ziegler started his career with the Athletics, pitching there from 2008 until a trade to the D-backs on July 31, 2011.
After a successful run in Arizona that ended abruptly on Friday night, Ziegler will soon be on his way to Boston.
Ziegler was told of the trade by manager Chip Hale in the seventh inning of Arizona's 6-2 loss to the Giants in San Francisco on Friday.
"I guess that's part of this game that you've got no control over, so there's no point in worrying about it or dwelling on it, but I thought there was a strong likelihood over the course of the next couple of weeks that something would happen," Ziegler said. "It was more the timing that caught me off guard than what actually happened."
Originally signed by Philadelphia as a 20th-round selection in the 2003 Draft, Ziegler is 32-24 with a 2.49 ERA (157 ER/567 IP) in 571 career appearances, all in relief with the A's (2008-11) and D-backs ('11-16).

He leads all Major Leaguers in pitching appearances and grounded into double play percentage (20.8, 108 of 520) since the start of 2008, and his ground ball rate of 67.4 percent is the highest among active relief pitchers (min. 750 batters faced).
With Ziegler gone in Arizona, Daniel Hudson and Tyler Clippard appear in line to receive save opportunities for the D-backs. Clippard has saved 54 games over his 10 year career, including 32 games with the Nationals in 2012. Meanwhile Hudson has just five saves in seven seasons.
Almonte, 20, was 2-2 with a 3.91 ERA in 10 starts for Class A Greenville this year. Basabe, 19, appeared in 64 games with Greenville and hit .310 with 16 doubles, four triples and four home runs. Basabe was named an All-Star in the South Atlantic League.
The Red Sox transferred Blake Swihart to the 60-day disabled list to clear roster space for Ziegler.
Dombrowski acquired third baseman Aaron Hill from the Brewers on Thursday, and utility infielder/outfielder Michael Martinez from the Indians on Friday.
• Hill immediately contributes in Red Sox debut
The Red Sox would like to acquire some starting pitching before the Aug. 1 non-waiver Trade Deadline.