Farquhar has appeared in seven games with the Rays this season, but he has spent most of the season in Durham. In 23 relief appearances spanning 24 2/3 innings at Triple-A, he is 3-1 with a 4.38 ERA.
Farquhar, who has also played with the Mariners and Blue Jays, is 4-12 with a 3.91 ERA and 18 saves in 165 appearances out of the bullpen. His best season was in 2014, when he posted a 2.66 ERA in 66 appearances with Seattle.
"With the guys that we have now that have come up -- Danny Farquhar, he can provide some length ... multiple inning-type stints," manager Kevin Cash said.
Webb was activated off the 15-day disabled list Sunday and with a track record of short outings, the team decided this was the best move, Cash said. In an appearance on Sunday, Webb allowed four runs on five hits in just one inning of relief.
Farquhar said he's not sure how much a middle reliever like himself can help a team that's lost 11 straight games, but he hopes he can bring a sense of veteran leadership to a clubhouse ravaged with injuries to some of its most experienced players.
"The most help I can be is keeping everything positive, and when the phone rings every third day in the bullpen and whenever my time is whatever the situation is, just be efficient out there, just get lots of outs," Farquhar said.
• Outfielder Brandon Guyer, who has been out since June 5 with a strained left hamstring, is the closest of any player on the disabled list to returning. He played designated hitter for Class A Advanced Charlotte on Saturday. After an off-day on Sunday, he was scheduled to play the field for the Stone Crabs on Monday for seven innings. He projects to be activated during this homestand.
• Fellow outfielder Steven Souza Jr. isn't far behind either. Out since June 15 with a strained left hip, he started running Monday and took batting practice.
"I'm not Superman," said Souza, who received an injection June 20 to reduce inflammation. "I'm not going to come on and get us on a 20-game winning streak or anything, but there's a lot of key pieces that obviously we need back."
• Pitchers Alex Cobb and Chase Whitley both threw bullpen sessions on Monday in their returns from Tommy John surgery. Closer Brad Boxberger threw at 105 feet on Monday and is tentatively scheduled to throw off a mound on Thursday.