Chicago needed to clear a 40-man roster space so that Gonzalez could open the season with the team following the news that Darwin Barney will begin the season on the disabled list.
Whitenack, 24, was an eighth-round pick by the Cubs in the 2009 draft but struggled through 51 1/3 innings at High-A Daytona last season. Whitenack posted a 5.96 ERA, 5.4 K/9, 4.7 BB/9, hit five batters and threw three wild pitches. Westnack had been in the midst of a breakout 2011 season before Tommy John surgery cut that effort short.
Baseball America ranked him 23rd among Cubs prospects this offseason, noting that his velocity was averaging just 90 mph after touching 96 mph in 2011 and that his slider had lost bite. If he can rediscover his 2011 form, BA feels that he has the ceiling of a No. 3 starter.