Rendon hit .240 (6-for-25) with one double, one RBI, five walks and two runs scored in eight games during his initial stint with Washington earlier this season. The 22-year-old, who was promoted from Harrisburg to Syracuse over the weekend, hit .307 with 12 doubles, two triples, six home run, 24 RBI and 19 runs scored in 36 games this season at Double-A and Triple-A. He posted 32 walks and a .452 on-base percentage with one stolen base at the two levels.
The Nationals' top selection (sixth overall) in the 2011 First-Year Player Draft out of Rice University, Rendon entered the '13 campaign rated as the Nationals' No. 1 prospect per Baseball America. He has pocketed a .408 on-base percentage with 38 extra-base hits, including 12 home runs, in 79 career minor-league contests.
In his first campaign with the Nationals organization, Krol posted five holds, one save and a 0.69 ERA (2 ER/26.0 IP) in 21 relief appearances with Harrisburg. He recorded 10.0 strikeouts per 9.0 innings (29 K/26.0 IP), a 4.1/1 strikeout-to-walk ratio and a .157 batting average against (.122 BAA vs. left-handed batters). The 22-year-old did not allow an earned run in his final 10 appearances with the Senators.
Acquired from Oakland on March 20, competing the trade in which the Nationals received right-handed pitchers A.J. Cole and Blake Treinen from the Athletics in exchange for outfielder Michael Morse (Jan. 16), Krol was Oakland's Minor League Pitcher of the Year in 2010, after going 10-4 with a 2.80 ERA in 28 games/7 starts at Kane County (Single-A) and Stockton (Single-A). In five seasons in the minors ('09-13), he went 12-14 with six holds, one save and a 3.46 ERA in 85 games/47 starts.
Espinosa, 26, is batting .158 (25-for-158) with nine doubles, three home runs, 12 RBI, four walks and 11 runs scored in 44 games this season with Washington.
The 26-year-old Rodriguez went 0-1 with one hold and a 4.00 ERA in 17 relief appearances this season with the Nationals.
Duke, 30, posted a 1-1 record and 8.71 ERA in 12 games/one start with Washington in '13.