A Fairfax, Va., native, Avery is a combined 13-12 with a 3.55 ERA in 147 games (14 starts) at the Minor League level. Avery, 25, was a Class A Midwest League All-Star in 2006.
Avery was the Cubs' ninth-round selection in the 2005 First-Year Player Draft out of the University of Virginia, where he played with third baseman Ryan Zimmerman for three years.
Buchter, selected by Washington in the 33rd round of the 2005 Draft, owns a 5.42 ERA in 48 games as a pro.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.