Zach Stewart was never a top prospect. He appeared on no top-100 lists for Baseball America, was drafted in the third round back in 2008, and doesn't really have much to show for the last three years in general.
Still, unlike so many minor leaguers, he's the sort of player who draws interest when his name is thrown into a trade. Maybe you've heard of him back when he was at the top of a bad Blue Jays system come the end of 2009. Maybe you heard of him from the Edwin Jackson trade. His was a name that was thrown around often enough that, even without the accolades, he could not simply be passed off as an add-on.
Still, by the time he came over to Boston in the Kevin Youkilis trade, Stewart had lost much of his luster. The rest would soon follow. While Stewart had been decent in Pawtucket upon joining the organization, when he made his way to the major leagues there was really no question that he was neither ready, nor seemed terribly likely to approach being ready anytime soon. Before he recorded even a single out, Stewart had surrendered four runs to the Los Angeles Angels. One more came in for the second inning, and by the time he was out of the third, the Sox found themselves in an amazing 9-1 hole.
One month later, Stewart got another shot, and once again imploded in grand fashion. While this time it was only 3-0 in the first, and 5-0 by the time he was mercifully pulled from the game, it was clear as day that whatever "it" was, Stewart didn't have it.
Maybe somewhere down the line the Sox will regret letting go of Stewart for the sake of 40-man space At one point talent evaluators saw something out of him, and while he pitched about as well in his two game for the Red Sox as you or I might be expected to, no two-game sample tells the full story, and late bloomers have been known to exist.
But it's better to not have a place for a guy like Stewart than to have one. At least when you consider the statement that makes about the relative health of the team. Our rotation may be questionable, but we're not that desperate.