As the sweepstakes for baseball's best free agents heats up, Manny Machado is sitting on an eight-year offer from the Chicago White Sox and is still engaged with the Philadelphia Phillies, while their pursuit of Bryce Harper grew stronger with an in-person meeting in Las Vegas over the weekend, league sources told ESPN.

The Phillies, as anticipated, could serve as the fulcrum for where two of the most talented free agents in a generation wind up, according to sources. Although a USA Today report deemed Philadelphia a "clear-cut favorite" to sign Harper, the Washington Nationals remain a possible landing spot for the 26-year-old outfielder, according to sources.

Philadelphia remains in the hunt for Machado, a 26-year-old shortstop/third baseman, and along with the White Sox, they've been told a third team is involved, according to sources. The White Sox have shown significant interest in Harper -- they met him in Las Vegas, his hometown, before the new year -- as well as Machado.

Chicago's willingness to offer a deal in the 10-year range has been questioned, as the largest contract in franchise history was Jose Abreu's six-year, $68 million deal. Guaranteeing eight years on Machado illustrates the seriousness of the White Sox in their pursuit, according to sources, and could portend the ability to proffer a decade-long offer -- especially if Philadelphia or the supposed mystery team continues engaging with Machado.

The slow-developing markets for Harper and Machado aren't necessarily indicative of teams' willingness to reach the $300 million threshold seen as a starting point for both players. The number of teams involved is smaller than anticipated, but Phillies owner John Middleton suggested to USA Today that his team might be "even a little stupid about" spending money this offseason, and the White Sox's transition from rebuilding to competitive in the American League Central is close.

Chicago already has traded for first baseman Yonder Alonso, Machado's brother-in-law, and signed outfielder Jon Jay, a close friend. The transactions by themselves haven't swayed Machado to deem the White Sox a favorite, but they were strong indications of Chicago's seriousness about signing Machado.