Spann, 22, went 4-3 with a 2.87 ERA in 19 games (four starts) for Bowling Green of the Single-A Midwest League this season.
After working primarily as a starter the last two seasons, Spann was moved to the bullpen most of this year, and posted a 2.50 ERA in 15 relief appearances.
The lefty had just 35 strikeouts and 21 walks in 59 2/3 innings and pitched to a 1.475 WHIP, but he allowed only five homers on the year.
Spann, who is 6-foot-7, 185 lbs., was a 25th-round pick of the Rays out of Central High School in Columbia, Tenn., in the 2010 First-Year Player Draft.
In essence, the Nats spun four days of DeJesus and some cash into Spann.
They acquired DeJesus from the Cubs on Aug. 19 in exchange for cash, and almost immediately placed the veteran outfielder back on revokable trade waivers. DeJesus got just three at-bats with the Nationals, then was claimed on waivers by the Rays.
The Nats and Rays were able to finalize a deal Aug. 23, sending DeJesus to St. Petersburg, and bringing the Nats a player to be named.
Spann is that guy, and he'll now provide more pitching depth within the Nats organization.
The Nationals have a Zimmerman and a Zimmermann. They have guy with the first name Jordan and a guy with the last name Jordan. And now they have a Span and a Spann.