Right-hander Drew Storen, the second of the Nationals' two No. 1 picks last year, is headed to the major leagues.
Storen, 23, will join the Nats' bullpen Monday night in St. Louis, according to a major-league source.
The Nats selected Storen 10th overall out of Stanford last June after taking right-hander Stephen Strasburg out of San Diego State with the first overall pick.
Strasburg almost certainly will remain at Triple A until after June 1, when he no longer will be eligible for an extra year of salary arbitration.
Storen allowed just two runs combined in 16 innings at Double AA and AAA, striking out 15 and issuing only three walks.
He projects as the Nats' future closer, but likely will start out pitching in the seventh inning in front of setup man Tyler Clippard and closer Matt Capps.