Well, I found out from a synopsis that he was hurt thanks to Marshmallow in Dewey's dog (oh, another cross episode reference!
), but I saw "Monkey" before I saw it.
Craig's roof injury in "Reese Drives" was completely unknown to me until I saw the episode. It was a bit of a surprise to me since he hadn't been injured in any of the other pre-"Dewey's Dog" eps and you wouldn't think they would put such a major injury so close to that ep...it creates confusion...
What I'm confused about is that Monkey chronologically comes before Deweys dog, making the line about MArshmasllow chasing him into the street pointless. It's possible they originally intended it to be from the roof injury, but that makes no sense either, seeing as Reese Drives is set BEFORE "Reese's Job" and "Lois' Makeover", both during which Craig is uninjured.
For reference, here are the production codes from Wikipedia
Reese's Job-310
Lois' Makeover-311
Reese Drives-309
Dewey's Dog-318
Monkey-315
Mind you, some of these production codes seem to make no sense. Monkey, in which Francis gets fired, was filmed mid-season, and Charity, during which Francis gets to Alaska, was produced before Book Club and Malcolm's Girlfriend, . I suppose the Alaska scenes were filmed for different episodes.
But look at the season 4 production codes...
http://en.wikipedia.org/wiki/List_of_Malcolm_in_the_Middle_episodes#Season_3_.282001.2
I'm guessing these shouldn't be trusted to be the "true chronological order".