The Chicago White Sox were far down the road on a trade Monday night that would send ace left-hander Chris Sale to Washington in exchange for the Nationals' top two prospects -- right-hander Lucas Giolito and outfielder Victor Robles -- and a low minor leaguer, a source told ESPN's Jim Bowden on Monday.

Two of the Nationals' other top pitching prospects, right-handers Reynaldo Lopez and Koda Glover, will not be in the proposed deal, the source told Bowden. The structure of the deal was first reported by Fox Sports.

Earlier Monday, White Sox general manager Rick Hahn said he wasn't budging in his asking price for Sale, likely the biggest prize of the winter trade market because of his All-Star résumé and relatively modest contract.

"When you have negotiations with other clubs about potential trade fits, you have to have that line you aren't going to go below; otherwise you're compromising too much in terms of value," Hahn said Monday afternoon.

Sale, 27, is coming off his fifth straight All-Star season in 2016, when he finished 17-10 with 233 strikeouts in 226⅔ innings pitched.

But he is on a very team-friendly deal that will pay him $12 million in 2017, with club options of $12.5 million for 2018 and $13.5 million for 2019.

"You've seen what this guy has done over the years," Hahn said Monday. "We realize this is an elite-level talent. A rare commodity in this league."

Information from ESPN's Jesse Rogers was used in this report.