It was also a night of supposed change for the Cubs, ahead of the 4 p.m. ET non-waiver trade deadline on Tuesday. Center fielder Reed Johnson and catcher Geovany Soto were replaced in the middle of the contest, with reports that both players had been dealt. Johnson and pitcher Paul Maholm were reportedly headed to Atlanta, and Soto to the Texas Rangers.
Darwin Barney blasted a three-run homer off Erik Bedard in the fourth inning and tied a career-high with four RBI. Castro went 3-for-4 and drove in three in Chicago's third consecutive victory.
Justin Germano (1-1), making his first start in a Cubs uniform, allowed four hits and a pair of runs over five innings. Germano, who was acquired earlier this month from Boston, made his first major league start since October 3, 2010 while he was with Cleveland.
Bedard (5-12) was shelled for seven hits and nine runs -- eight earned -- over 4 1/3 frames to suffer his sixth defeat in his last seven decisions.
Michael McKenry knocked in two runs for the Pirates, losers of two in a row following a four-game winning streak. Starling Marte had three hits and an RBI.