I think it's about time to give that thing a yank.  While Sidney didn't get hammered again tonight, I think it's safe to day that it was another sub-par performance.  He was in trouble a lot, and he made key mistakes to the Royals' two best hitters.  Through 4 starts, his numbers look like this:

W-L    IP    H    R   ER  HR  BB    K   WHIP   BAA
1-3   21.1  35  20   20   6    9    12    2.06   .361

Ugh.  Ponson's next scheduled day to start would be Monday.  Luckily, the Twins have that day off.  I see no reason not to skip him.  The next day the Twins will need a fifth starter will be Saturday, May 5th when they host the Red Sox.

In my opinion, Sir Sidney must be on thin ice with cracks forming beneath his feet at this point.  The Twins have a few options right now, actually.  They could cut him now, and start Perkins, Guerrier, or maybe Slowey on May 5th (Garza hasn't found a groove yet).  Or the Twins could send Perkins down when Cirillo comes back and give Ponson the start on May 5th.  The Twins (knowing them well) might even decide to let Ponson pitch on May 1st.

In my opinion/prediction the Twins will let him have one or two bad starts before cutting him.  By then, it would be mid-May and someone in AAA (probably Slowey at this point) will be ready to get a shot at the 5th spot in the rotation.  It seems like a decent plan to me, even though the Pessimistic Twins Fan in me wants him driven out of town by an angry mob tonight.