Ahead of next month’s Rule 5 Draft, the Nationals selected the contracts of infielder Yasel Antuna and right-hander Joan Adon, protecting the prospects from being chosen by another club. With these moves, the Nats' 40-man roster stands at 33.

Antuna, Washington’s No. 12 prospect per MLB Pipeline, and Adon, their No. 16 prospect, were part of the Nationals' 60-man player pool this year. They spent the season at the alternate training site in Fredericksburg, Va., and took part in the team’s instructional league this fall. Both signed with Washington on July 2, 2016.

• Why is the 40-man roster so important?

The switch-hitting Antuna was named the organization’s Minor League best hitter for average and best power hitter by Baseball America. At 21 years old, he has played shortstop, third base and second base while batting .247 with 124 hits, 70 runs, 44 RBIs, 22 doubles, seven homers and 13 stolen bases over three seasons in the Minors.

Adon made 21 starts in 2019 for Class A Hagerstown and pitched to an 11-3 record and 3.86 ERA across 105 innings. The 22-year-old struck out 90 batters that season, and his 11 wins tied for second among South Atlantic League pitchers. Overall, he is 16-5 with a 3.85 ERA in three Minor League seasons.

The 2020 Rule 5 Draft is scheduled for Dec. 10, when teams without a complete 40-man roster can select specific non-40-man roster players from other clubs. Players drafted out of college in ‘17 at age 19 or older, and those drafted out of high school, plus international players signed in ‘16 at age 18 or younger need to be protected in order to avoid being picked.

Rule 5 Draft-eligible players who were not protected by the Nationals this year include catcher Israel Pineda (No. 14), right-hander Sterling Sharp (No. 24), catcher Raudy Read (No. 27), outfielder/second baseman Cole Freeman (No. 28), outfielder Nick Banks (No. 29) and catcher Jakson Reetz.