Cedeno, 28, rejoins the Nationals for the fourth time this season. The left-handed reliever has not allowed a run at the Major League level this season, scattering four hits in three appearances (3.1 IP) with one strikeout. At Triple-A, Cedeno was 5-1 with a 2.29 ERA in 35 games (39.1 IP). While holding International League batters to a .163 average against and possessing a 0.86 WHIP, Cedeno has struck out 57, walked 12 and allowed just 10 earned runs. Against left-handed batters, his ERA drops to 1.35.
Leon, 25, strengthens the Nationals' catching corps for the stretch run in his fourth Major League stint of the season. The switch-hitting catcher hit his first Major League home run on April 14 off Kevin Slowey in Miami, and posted a .169 average in 18 Major League games this season. Leon hit .229 for Syracuse with five home runs and 25 RBI. Known for his above-average defensive skills behind the plate, Leon has caught 45 percent of attempted base stealers over the course of eight Minor League seasons.
Moore, 27, makes his third return to the Nationals' Major League roster this season, adding power and versatility off the bench. In 34 Major League games (16 starts) this season, Moore hit .214 with three home runs and 11 RBI. The first baseman/outfielder hit .265 with a .367 on-base percentage and a .434 slugging percentage at Triple-A this season, clubbing 31 extra-base hits and driving in 44 runs in 84 games. In 46 career big league games as a first baseman, Moore has hit .325 with eight doubles, six home runs and 26 RBI.
Treinen, 26, rejoins the Nationals for the sixth time this season. He is 1-3 with a 2.35 ERA in 11 Major League games (five starts) this year. The right-hander earned his first MLB win on June 28 at Wrigley Field when he held the Cubs to two earned runs over 5.0 IP. As a starter in the majors, Treinen has worked to a 2.50 ERA, and as a reliever he's posted a 1.54 mark. Treinen had an 8-2 record with a 3.35 ERA in 16 starts at Triple-A this year.
Souza Jr. returns to the active roster after missing 20 games with a left shoulder contusion. The 25-year-old, who was named the International League MVP last week, led the league in almost every offensive category: batting average (.350), on-base percentage (.432), and slugging percentage (.590). He also hit 18 home runs, drove in 75 and stole 26 bases. Souza Jr. is 1-for-12 (.083) with one walk and four strikeouts in the Major Leagues this year.
The Nationals' call-ups helped the Chiefs clinch their first IL North Division title in 25 years on Saturday night. The players will join the Nationals before the start of their three-game series at the Los Angeles Dodgers on Monday evening.