When a pitcher is terrible, the Angels have, historically, not really stuck with him too long. The advanced stat of ERA+ equalizes pitcher performance to league averages across time. An ERA+ of 100 means that a pitcher was perfectly average to the competition. Higher than 100 indicates better pitchers (Jered Weaver's career ERA+ is 128). Lower than a hundred indicates a pitcher who is below average (Jason Isringhausen's one season in Anaheim yielded an ERA+ of 92).
In examining the stats compiled by every Angels pitcher in team history, all 418 of them, of the 201 Angels pitchers recording an ERA+ under 90 in all their games pitched as an Angel, only five of them pitched more than 300 innings:
SHAWN BOSKIE - 89 ERA+ in 301 IP thrown in 1995 and '96
TOM MURPHY - 87 ERA+ in 795 IP thrown from 1968-72
AARON SELE - 85 ERA+ in 413 IP from 2002 thru '04
JIM SLATON - 84 ERA+ in 384 IP from 1984 thru '86
To give you a recent comparison, Dustin Moseley, Sean O'Sullivan and Esteban Yan each recorded an ERA+ of 84 in their short Angels careers, but they pitched 168, 64 and 89 innings total in their careers while wearing a Halo. The Angels have stuck with that low level of pitching only a few times - and we are talking fifth starters all the way.
In only one Angels career was a pitcher allotted a substantial amount of innings in a season and allowed to return worse than those mediocrities...
CHRIS KNAPP - 75 ERA+ in 403 IP from 1978 thru 1980
How bad was Chris Knapp? If you go by the idiotic WIN stat, he was aided and abetted by an awesome Angels offense as his 5.08 ERA over 400+ IP still garnered 20 Wins in 82 games, 67 of them starts. He allowed 420 hits, 51 of them homeruns. Troy Percival allowed 27 fewer hits in 183 more Innings Pitched than Chris Knapp.
Perhaps worst of all, he was allowed to start a playoff game. Not only that, he was picked to start an ELIMINATION playoff game. Knapp started Game 4 of the best-of-five 1979 ALCS. He was pulled in the third inning, allowing 2 Earned Runs on 5 Hits. Yep, they were eliminated alright.
Knapp came over to the Angels in a trade after the 1977 season that brought over pitcher Dave Frost and the god-like Brian Downing. The Angels definitely won that trade with the awesome career that Downing would have in Anaheim alone and it is a pity that the team stuck with Knapp all that time.
But now you know - nobody has thrown that many innings for the Angels and performed that poorly. If the argument that Tom Murphy's 700+ innings of 85 ERA+ outweighs Knapp's crap, understand that none of Murphy's teams were going anywhere. The 1978 Angels could have gone further with one better pitcher and the '79 team was demonstrably shortchanged by his stunning lack of delivering even low-level mediocrity.
I am sure Chris Knapp is a nice guy. He was a lodestone to the Angels.