The World Series champion Chicago Cubs could be on the verge of fortifying their bullpen once again - but not if one of their NL rivals gets in the way.

Chicago is reportedly nearing a trade to acquire Kansas City Royals All-Star closer Wade Davis, according to Buster Olney of ESPN. But that deal could be further away than it once appeared, as negotiations between the teams have reportedly hit a "snag," reports Jeff Passan of Yahoo Sports.

That snag could be the Washington Nationals, who are reportedly making a late push to acquire Davis and fill their vacated ninth-inning role, reports ESPN's Jayson Stark. It's not clear how far along those talks are.

The possible returns for Davis from either Chicago or Washington are not yet known.

Another factor in delaying the proposed deal to Chicago might be Davis' health, according to Ken Rosenthal of FOX Sports, who reported the Cubs need to sign off on his medicals before finalizing the deal with Kansas City. Despite his effectiveness last year, Davis hit the disabled list twice with the same injury - a flexor strain - and missed all of August due to recurrence of the ailment.

If the trade to Chicago is completed, Davis would step into the closer's role that was left vacant when Aroldis Chapman reached free agency. Though they have been connected to both Chapman and another free-agent stopper in Kenley Jansen, a Davis deal would likely close the door on either of those players signing on with the North Siders.

An All-Star for the Royals each of the last two seasons, Davis formed the backbone of the team's bullpen during their back-to-back AL pennants in 2014 and '15. Since 2014, when he became the Royals' set-up man, the 31-year-old has been lights out, posting a 1.18 ERA, averaging over 11 strikeouts per nine innings, and allowing just three home runs. Davis allowed just one earned run in 20 postseason appearances for the Royals.

Davis, who will be a free agent after this season, is owed $10 million in 2017.