My WAR calculation is a combination of Baseball-reference and Clay Davenport; I believe it to be the "best" WAR number available for historical comparison. 8 WAR is an MVP quality season. The record is pythagorean adjusted for 162 games.
1899 66-96
C Jack Warner -.4
1B Jack Doyle 2.2
2B Kid Gleason .4
SS George Davis 4.85
3B Fred Hartman -.05
LF Tom O’Brien .85
CF George Van Haltren 1.1
RF Pop Foster -.4
Uti Parke Wilson .2
OF Mike Grady 2.7
OF Mike Tiernan -.8 (43.2) Last Season
P Bill Carrick 1.25
P Ed Doheny .3
P Cy Seymour 5.7
P Jouett Meekin .7 (24.1) Last Season
P Charlie Gettig -.2
Full crater here; worst Giants team to that date, it's managed by a one time owner (the Giants have been sold a couple of times in the 19th century) and the new century can't come quickly enough. Tiernan and Meekin finish their Giants careers and hit the all time list. Tiernan's the last Giant from the '80s (until O'Rourke's brief comeback five years later) and he retires as a Pureblood Giant - played for no other team in his career.