As Tony Olivero writes in The Wall Street Journal, Tim Lincecum hasn't merely been lousy this season; at his current pace, he'll finish with arguably the worst pitching season in major league history.
Lincecum currently has a 55 ERA+, which is essentially a pitcher's ERA relative to the league, with contextual adjustments. Since 1901, there has literally not been a single pitcher who finished a season with at least 95 innings and an ERA+ lower than 56.
There have, on the other hand, been three pitchers with at least 95 innings and a 56 ERA+ on the nose: Carl Lundgren (1908), Rube Bressler (1915) and Bill Stoneman (1973). Olivero:
Lincecum especially doesn't want to become the next Lundgren. Lundgren had the second-lowest ERA in baseball in 1907 before imploding in 1908—the year of the Chicago Cubs' last World Series title. After 1908, he pitched just two more major-league games.
Those other two guys didn't exactly cover themselves in glory, either. Bressler hardly pitched at all in 1916 and '17, and ultimately became a pretty good first baseman and outfielder. Stoneman lasted just one more season, in which he went 1-8 with a 6.14 ERA.
All three of those guys combined for 13 wins after the seasons in question, and I'll bet just about anything that Lincecum wins a lot more than 13 games after this season. For one thing, the doctors are a lot better than they were in Lundgren and Bressler's era, and even in Stoneman's.
For another -- and I know it's a dead drum but by Gosh we're going to keep beating it until the skin breaks -- Lincecum's pitched a lot better than his 6.42 ERA suggests. His fielding-independent numbers suggest a sub-4.00 ERA, and fielding-independent numbers predict ERA better than ERA predicts ERA.
I don't think he's the pitcher that he used to be. I do think he's better than the pitcher we've seen this year. And he's not setting some futility record.