Nationals call up Stammen for start
The Nationals placed right-hander Tyler Walker on the 15-day disabled list, retroactive to June 20, because of an AC joint sprain in his right shoulder.
The 26-year-old Stammen was optioned to Syracuse on June 6 with a 1-2 record and 5.43 ERA. He was 2-0 with a 2.25 ERA in three starts with Syracuse.
Walker is 1-0 with a 3.57 ERA in 24 games.
Copyright 2010 by The Associated Press