Jeff Passan breaks down the Dodgers' acquisition of Mookie Betts, saying the deal makes them the heavy favorites to win the National League. (1:47)

The blockbuster three-way trade that would send star outfielder Mookie Betts and starter David Price to the Los Angeles Dodgers has been held up due to questions regarding the health of one player involved in the deal, though officials with the teams remain confident it will be completed, sources familiar with the situation tell ESPN.

The deal, which would send Betts and Price to the Dodgers, outfielder Alex Verdugo and pitching prospect Brusdar Graterol to the Boston Red Sox and starter Kenta Maeda to the Minnesota Twins, was not completed Wednesday after being agreed upon Tuesday night. The Red Sox, sources said, were spooked by a medical review of Graterol, the hard-throwing 21-year-old right-hander who has undergone Tommy John surgery and missed time in 2019 because of a shoulder injury.

Alternative options to complete a deal exist, according to sources. The players involved could be amended, as could the amount of money Boston is sending to Los Angeles to cover a portion of the $96 million still owed Price. The Dodgers and Red Sox could theoretically opt for a two-team deal or involve a different third team; Graterol is currently with the Twins.

The likelihood of the trade of Betts to the Dodgers blowing up altogether, sources said, is slim, as medical-related impasses are typically worked around. Although the negative reaction in Boston to trading Betts, a homegrown franchise player, was loud and abundant, it was not a driving force behind the holdup, sources said. Boston simply wants to ensure that it receives a commensurate return for the 27-year-old right fielder, who is entering his final season before free agency and is expected to seek a contract well in excess of $300 million and perhaps even $400 million.

The three-way trade is tied to another proposed deal in which the Dodgers would send outfielder Joc Pederson, starter Ross Stripling and prospect Andy Pages to the Los Angeles Angels for infielder Luis Rengifo and a prospect, according to sources. By offloading Pederson, the Dodgers would remain underneath the $208 million luxury-tax threshold, even after taking on the hefty salaries of Betts and Price.

Boston's motivation to dip beneath the threshold was a strong part of its motivation to deal Betts, sources said. Packaging Betts and Price would allow Boston to shed more than $40 million in payroll this season and reset future luxury-tax consequences instead of exceeding the threshold for the third consecutive season and compounding the penalties for doing so.

The holdup, first reported by The Athletic, "is a problem but one we can figure out," according to a source involved in the deal. With pitchers and catchers due to report to Red Sox and Twins camp Wednesday and Dodgers camp Feb. 14, the incentive to find a quick resolution is strong and work will continue Thursday.