Newsflash: Madison Bumgarner is good.
How good? Well, let's see.
We'll start backwards with the San Francisco Giants lefty and examine his post-season record. Through the tender age of 24, Bumgarner has already made 11 post-season starts and one relief appearance, pitching a total of 74.1 innings, allowing 21 earned runs (22 total) for a 2.54 ERA. His components are excellent: a 65/19 K/BB ratio and a mere 57 hits allowed. He's been a bit home run vulnerable with seven gophers given up, but he's been outstanding in three World Series starts, allowing one run in 22 innings of work with a 19/5 K/BB and an incredible eight hits.
You may know all that watching the post-season games, but as Giants fans are well aware, he's been impressive in the regular season. He's 67-49, 3.06 ERA, 3.15 FIP, with an 896/229 K/BB in 953 innings. He's rang up 16.2 WAR already in four and a half seasons of work.
In historical context, this puts him in some elite company. His Top Ten Sim Scores are Vida Blue, Dave Boswell, Dizzy Dean, Felix Hernandez, Ross Grimsley, Bob Moose, Clayton Kershaw, Hal Schumacher, Ken Holtzman and Robin Roberts.
We don't know how Hernandez and Kershaw will turn out, but of the other eight we have two Hall of Famers in Dean and Roberts. Blue pitched like a Hall of Famer early in his career but wore down due to overuse and personal problems, though his career was still highly successful overall with 209 wins and 3343 innings. Moose was strong through age 25 but then his arm fell off.
Schumacher is little-remembered today, but he was a very good pitcher who threw 2482 innings with a 111 ERA+, winning 158 games in the 1930s and 1940s, despite missing three seasons due to World War II. Holtzman was also a workhorse, similar to Schumacher, winning 174 games in the 60s and 70s, throwing 2867 innings (105 ERA+ but stronger early) until his arm fell off at age 33.
Grimsley was strong through age 24, lost some effectiveness at that point and became an adequate inning-eater, rebounded with a 20-win season at age 28 then fell apart again and was done as an effective pitcher at 30. He still threw over 2000 innings and won 124 games. Boswell was excellent early and won 20 games at age 24, then his arm exploded. He was finished as an effective pitcher at 26.
That's an impressive historical context for Bumgarner: two Hall of Famers in Dean and Roberts, two long-term successful workhorses in Schumacher and Holtzman, a 209-game winner in Vida Blue, and three other guys who started off strong but ran into the ground due to old-style usage patterns or off-field issues. The latter don't seem like they are going to be a problem in Bumgarner's case.
He could still get hurt of course, but unless the Giants go completely nuts with his workload, I think there's a good chance he'll remain strong through the remainder of his contract (which runs through 2019 with team options).