Go read Bastian's piece, then come back. Ok, good.
Given that the Jays 30+ year history has seen significant changes in the way the game is played and the pace of run scoring has varied greatly (remember the scrawny guys with bad mustaches in the '70s and '80s and the roided up sluggers in the mid '90s to early '00s?) , let's agree that ERA+ is a better measure of a staff's success over the years than raw ERA.
As everyone should know, OAC Finite, or "gambling math", is the only math worth learning. Nevertheless, baseball-reference describes ERA+ with the following esoteric formula that looks something like calculus:
- ERA+ - the ratio of the league's ERA (adjusted to the pitcher's ballpark) to that of the pitcher. > 100 is above average and <>lgERA / ERA
The Jays current staff ERA+ stands at 121 and probably won't change much with only 15 games remaining. That number bests the '92 (105) and '93 (103) Jays, who had a bit of team success, in addition to the '98 Jays (107), whom I mention only because they set the post-Glory Days high water mark for wins at 88.
And the ERA+ leaderboard through franchise history:
1985 - 129
2008 - 121
1987 - 121
1991 - 121
1997 - 115
1982 - 114
2007 - 112
The low ERA teams Monsieur Bastian cites as besting the current Jays staff are the 1989 A's (who laid a pummeling on the Jays in the ALCS) and the 1981 Yankees in a strike-shortened season.
The latter posted a team ERA+ of 118, while the former put up an impressive 123. I think it's fair to speculate that had the '81 Yankees played an additional 55 games for a full season, 36-year-old Rudy May and 38-year-old Tommy John would've seen their ERAs rise, though by how much is a matter of conjecture. Goose Gossage too posted an unreal ERA+ of 461 through 46.7 innings with good, but not unworldly, peripherals. I think their bully would've regressed a bit is what I'm saying.
There's no sortable way I know of to rank teams from 1977 on based on ERA+, so off-hand here are some other teams that popped into my head:
* The 2005 Chisox coasted to a World Series triumph with a relatively weak offense (that did sock dingers like nobody's business) on the backs of an excellent staff that put up an ERA+ of 124.
* The 2004 Bosox put up a 116... and won the World Series to everyone's great dismay. And a 123 in repeating that dirty, unspeakable act again last year.
* For sheer excellence year in, year out, look south. The Braves put up a wicked 129 in 1993, 124 in strike-shortened 1995, 124 again in 1996, 131 in 1997, 128 in 1998, 123 in 1999, 124 in 2001, and capped it with a savage 133 in 2002 before falling to more mortal levels in recent years. That impresses me greatly and the 2002 Braves probably had the best staff of the past 3 decades.
* The 2001 Mariners team that won 116 f'n regular season games before losing to the Yankees in the first round of the playoffs "only" put up a 118. Pussies.
* In the way back file, the 1979 AL Champ Baltimore Orioles had the best pitching of the great Earl Weaver teams of the late '70s and early '80s, putting up a 123.
It kind of sort of looks like the best AL staffs since 1977 were 2005 Chisox, the 2007 Bosox, the 1979 Orioles and 1981 Yankees in that order, but don't quote my fake internet pseudonym on that. If someone wants to invest more time into making a more comprehensive list, I invite you to delve into this long, hard slog and correct my work.
As it stands, it looks like the 2008 Jays do have a decent chance of finishing the season with the 2nd best staff ERA+ in team history, but will have to step it up a collective notch to best last year's Bosox and the 2005 Chisox. I don't think that takes away from the accomplishment, but does put it in perspective a bit.
Beer o'clock. Go Jays!
-- Johnny Was