The White Sox just traded Edwin Jackson and Mark Teahen to Toronto for Oak Forest native Jason Frasor and pitching prospect Zach Stewart. You can get Major League trade analysis anywhere, but this is a minor league blog so we're going to talk about the minor leaguer the Sox received.
Zach Stewart pitched for three colleges in three years. He was drafted in the third round by Cincinnati out of Texas Tech, where he was a reliever. He began his pro career in the bullpen with strong results in A ball that year.
Entering 2009, Baseball America rated Stewart as the 15th best prospect in the Reds' system. They mentioned how he could be in a Major League bullpen quickly. They said his fastball sat 93-96 with sink and he had a slider that could be called an out pitch. That year the Reds gave him some starts in high-A where he pitched well enough to earn a promotion to AA, where he maintained solid control and a sub-two ERA.
In AAA, Stewart was moved back to the 'pen and then ultimately traded to the Blue Jays in the Scott Rolen trade. The Jays kept him in the bullpen in AAA.
BA named him Toronto's top prospect entering 2010. This time around they say his slider was his best pitch and that the move to the bullpen at the end of '09 was to minimize his workload that year. Improvement in his changeup is also noted. Stewart spend the entire year starting in AA and posted a 3.63 ERA.
Stewart moved down to No. 6 in BA's Toronto rankings this year (The Roy Halladay trade added some guys that bumped Stewart). They say he has two plus pitches, fastball and slider, but could be a decent mid-rotation starter because his change is decent enough. This year, repeating AA, his ERA was 4.20. He made three starts in the Majors this June (4.86 ERA).
If you read the links below, the consensus is that Stewart will be a Major League caliber pitcher. No one seems to be sure if he will be a No. 3/4 type starter or a closer though.