JUPITER, Fla. - The player to be named is no longer nameless.
Morse was shipped to the A's in exchange for Krol and right-handers A.J. Cole and Blake Treinen. Oakland then flipped Morse to Seattle for catcher John Jaso.
The 21-year-old Krol was drafted by the A's in the seventh round of the 2009 First-Year Player Draft. In four seasons on the A's farm, he went 12-14 with a 3.75 ERA in 64 games, 47 of them starts.
He was named Oakland's minor league Pitcher of the Year for 2010 after going 10-4 with a 2.80 ERA in 28 games (27 starts) with two Single-A clubs, Kane County of the Midwest League and Stockton of the California League.
Last year, the curveball specialist was 1-7 with a 5.21 ERA for Stockton and 1-2 with a 5.06 ERA at Double-A Midland. Through his minor league career, he has 210 strikeouts and 55 walks in 244 2/3 innings pitched.
Krol was suspended for more than two months during the 2011 season as a result of a Twitter posting that included a homophobic slur. The ban came as he was preparing to return to action following a forearm injury. While at Neuqua Valley High School in Napierville, Ill., he was suspended during his senior season for an alcohol-related issue.
The Nationals will assign him to a minor league team once he reports to minor league camp in Viera.