McGregor lost a megabucks fight in August against the unbeaten Mayweather, who defeated Pacquiao in their disappointing ‘Fight of the Century’ in 2015.
“Happy Thanksgiving! Stay fit my friend. #realboxingmatch #2018 @thenotoriousmma,” Pacquiao posted on Twitter and Instagram, using McGregor’s social media handle.
There was no immediate reaction from McGregor on social media, and Pacquiao’s media team told AFP Friday that there were “no negotiations yet” about a McGregor match.
Pacquiao, who turns 39 in three weeks, lost his World Boxing Organization welterweight title to Australian former teacher Jeff Horn in July, having come out of retirement in 2016 to take the belt from American Jessie Vargas.
McGregor has not fought in mixed martial arts or boxing since losing to Mayweather by 10th-round technical knockout in their much-hyped bout in Las Vegas in August.
Pacquiao’s “#realboxingmatch” reference appears to be a swipe at Mayweather, who beat the Filipino by unanimous decision in 2015 in the richest fight in boxing history.
Pacquiao, who fought with a shoulder injury that later required surgery, has insisted he beat Mayweather, saying he “didn’t do nothing. He was always moving outside”.
Mayweather retired with a record of 50-0 after the McGregor bout.