Entering the past three Trade Deadlines as serious contenders, the A’s have not hesitated to make the jump on deals they believe increase their chances of making a deep playoff run.

This year is no different.

With a clear need for relief help, the A’s officially added a strong bullpen reinforcement with left-hander Andrew Chafin in a deal with the Cubs on Monday night.

In return, Oakland sent the Cubs outfielder Greg Deichmann, ranked by MLB Pipeline as Oakland’s No. 9 prospect, and Low-A right-hander Daniel Palencia.

The 31-year-old Chafin, whose contract includes a $5.25 million mutual option for 2022 with a $500,000 buyout, has emerged as one of the top left-handed relievers in baseball this season. In 43 appearances with the Cubs, he’s posted a 2.06 ERA with 37 strikeouts and 12 walks across 39 1/3 innings pitched. Chafin has been tough on hitters on both sides of the plate, though he’s actually fared slightly better against righties, holding them to a .147 batting average as opposed to a .164 average against lefties.

Used primarily as a setup man to Cubs closer Craig Kimbrel this year, Chafin could fill a similar role with Oakland closer Lou Trivino. Upgrading a bullpen whose 15 blown saves is tied for fourth-most in the American League, Chafin provides A’s manager Bob Melvin another high-leverage option from the left side along with Jake Diekman, and could form a bridge tandem to the ninth inning with veteran right-hander Yusmeiro Petit.