Or maybe both? Through Thursday's disaster the Angels have allowed a league worst 166 runs, 37 more than the average team. Who's most to blame? I've alternated on this issue, depending on whether I'm watching another relief pitcher who can't find the strike zone, an outfielder jogging after a ball that winds up dropping 5 feet in front of him, another line drive, an infielder bobbling a routine chance, a gopherball, or catcher playing catch with Torii Hunter. So let's see what the numbers say:
This year there are 3 defensive systems freely available this year, UZR is on Fangraphs for the second year, John Dewan's defensive runs saved joins the Fangraphs pages, and baseball reference has added Total Zone to it's pages (a metric invented by an Angel fan from what I understand.) Those metrics don't always agree, especially for individual players. The approach I prefer to take is to look at them all, and combine that with my own observation.
Anyway, all three agree the Angels have not fielded well. TZ has a -15 (including catcher SB allowed), UZR -9, and DRS -7. The Angels have a defensive efficiency rating (a Bill James invention) of .667, next to last in the league. This indicates they have allowed about 20 more hits than an average team would. The consensus seems to be the Angels defense has been 10-15 runs below average this year.
That means the pitching is responsible for 22-27 runs below average, and deserve the majority of the blame. Specifically, they have walked 18 more batters than average (seems like more than that), and a walk is worth about a third of a run (6 runs). They have allowed 11 more homers than average, at 1.4 runs per homer that's 15 runs.
So the math adds up. Blame about 2/3 of the suckitude on the pitchers, and a third on the defense.