To get reliever David Robertson from the White Sox, the Mets would have to include Michael Conforto in the deal, team sources told Daily News reporter Kristie Ackert.

According to Ackert, though the they haven't ruled out adding Robertson to their bullpen, a source with the White Sox told her the Mets have not made a serious attempt to acquire him this offseason.

Newsday's Marc Carig reported something similar two weeks ago, also citing a team source.

Robertson, 31, will earn $12 million in 2017 and $13 million in 2018. He had a 3.47 ERA (3.58 FIP) and 37 saves for the White Sox last season, striking out 75 batters in 64 innings.

In September, he had arthroscopic surgery to clean up a meniscus issue in his left knee, though the White Sox have said he'll be 100 percent for the start of spring training.

Mets GM Sandy Alderson has repeatedly said this offseason that he'd like to add at least one high-leverage reliever to his bullpen before the start of spring training.