The Washington Nationals today selected the contract of right-handed pitcher Blake Treinen from Triple-A Syracuse and optioned right-handed reliever Aaron Barrett there. Additionally, the team recalled outfielder Steven Souza Jr. and placed outfielder Denard Span on the 7-day Disabled List with a concussion. Nationals President of Baseball Operations and General Manager Mike Rizzo made the announcements.

Treinen, 25, made one start for Triple-A this season (April 7 vs. Pawtucket), tossing five innings and allowing just three hits. He did not allow an earned run, walked two and struck out four batters. A power right-hander, Treinen has a 3.73 career ERA in 69 Minor League games (38 starts). This will be his first Major League assignment.

A seventh-round draft pick of the Oakland Athletics in the 2011 First-Year Player Draft (No. 226 overall), Treinen was acquired by the Nationals, along with right-hander A.J. Cole and left-handed reliever Ian Krol, from the Athletics in the three-team trade in Jan., 2013, that sent outfielder Michael Morse to the Seattle Mariners.

Souza Jr., one of the Nationals' top 10 prospects as ranked by Baseball America, is hitting .273 with a .429 on-base percentage and a .545 slugging percentage in seven games for Triple-A Syracuse this season. Souza has clubbed two home runs, walked six times and struck out on just four occasions. He has also driven in seven runs.

A third-round selection of the Nationals in the 2007 First Year Player Draft (No. 100 overall), Souza Jr., 24, has hit .247 in 629 Minor League games with 209 extra-base hits (117 doubles, 15 triples and 77 home runs) and 351 RBI. Since the start of the 2012 season, Souza Jr. has posted a .296 batting average. This will also be his first Major League assignment.

Barrett, a rookie who made the Nationals out of Spring Training after a strong performance in Major League camp, pitched in six games (4.1 IP) and did not allow an earned run. Of the 16 batters Barrett faced, he allowed just one hit, walked only two and struck out six.

Span is hitting .222 this season with a .300 on-base percentage, three doubles, a triple, four walks and four RBI. He suffered the injury in a collision with Braves second baseman Dan Uggla on the basepaths on Friday night.

Additionally, infielder/outfielder Jeff Kobernus was recalled from Triple-A Syracuse and placed on the 60-day Disabled List with a left hand fracture.