Severino, who entered the season rated as the "Best Defensive Catcher" and the No. 11 prospect in Washington's Minor League system (per Baseball America), is hitting .259 with 11 doubles, two homers, 17 RBI, 17 walks and 23 runs scored in 73 games for Triple-A Syracuse.
Severino was recalled for his first Major League assignment of the season on April 26 when catcher Wilson Ramos was placed on the bereavement list. He appeared in one game, making the start on April 28 vs. Philadelphia, and was optioned back to Triple-A upon Ramos' return on May 1.
A native of Bonao, Dominican Republic, Severino is in his sixth season in Washington's system, signing as a non-drafted free agent, December 13, 2010. He has thrown out 36 percent of attempted base stealers over his Minor League career.
Lobaton, 31, is hitting .194 with one double, one triple, three homers, six RBI, 10 walks and eight runs scored in 27 games this season. The Nationals are 67-51 since 2014 when he starts at catcher. This will be Lobaton's first trip to the disabled list since April 15, 2012 as a member of the Tampa Bay Rays (right shoulder soreness).