The problem was never the sources, the problem was always the way the story was constructed. As opposed to taking the evidence, which was, as it now appears, very typical, par-for-the-course locker room interpersonal conflicts, and writing a story about what the available pieces of information were, allowing the audience to draw conclusions based on them, Werder's article reads like something that was created long before any sources were made available.
The list of examples of such manipulation, even when subtle, is long:
First, when you read Bradie James' quotes, it's actually quite obvious that they don't have to do with the particular situation referred to by the anonymous source but rather pertain to more general questions of interpersonal conflict. But the positioning is key. James quote says that, when problems arise, "We all talk...there's no dislike." But somehow Werder editorializes his leadin to the quote with a claim that James acts as "Peacemaker," a claim no one made and a statement unsupportable by the quote attached. This is Werder making things up.
Second, ESPN still has a false sub-headline in a side-bar to a Mosley story. Right now this side-bar is headed, "Mosley: Secret meeting", but then goes on to describe a series of meetings that were in no shape or form secret.
Third, Werder editorializes about the fault and reasons for Owens' departure from SF and Philadelphia, claiming in a story that is otherwise positioned as fact and news that Owens previous behavior was the cause of problems with former quarterbacks.
Fourth, Werder editorializes, without any support, that "Owens seems to be finding it increasingly difficult to conceal his irritation." This was his original premise, created before any evidence was available, so he makes it without support.
Fifth, Werder takes advantage of having spoken to more than one (probably two, at most three) Cowboys by intimating that the entire team is rising up against Owens, by stating, "But what upset Owens' teammates most of all was his response to the interception Romo threw on a pass intended for Witten..." Using the vague "teammates" is a cheap way to push his personal view without being responsible for the truth of the insignificant numbers of those who were actually upset by his reactions.
Sixth, Werder does it again, but this time with "Cowboys insiders." Maybe it's two and maybe it's three, but as long as Werder can tack that plural on, he can push his "the entire lockerroom is breaking down" theory that isn't supported by the data.
Seventh, Werder pushes this tactic even further by using a pernicious construction, "At least one." This is editorialization by language at its finest. While technically true, saying that "at least one prominent player was displeased..." is a way of Werder communicating, with a wink and a nod, "I only have one source on this, but between you and me, we know it's more, because we've all made our minds up that this is a huge, universal collapse, and not a small issue with a few people involved. Right?"
Eighth, Werder uses language intentionally positioned in an aggressive way to the target, claiming that "Phillips justified Owens" and "Jerry Jones further empowered him." Pure editorialization with the implication that TO is somehow a negative character with illegitimate arguments that must be "justified" and "empowered."
Ninth, Werder buries the obligatory mention of all of the counterpoints to his master theory in the very final paragraphs of his article.
The "making things up" nonsense is a red herring. Blowing things far, far out of proportion relative to similar situations in other locker rooms because of the newsworthiness and political implications (TO trashing Emmitt and Keyshawn the very DAY before the article went out) of the individuals involved, writing a story to fit his own preconceived notions and taking advantage of the absurd immunity of anonymous sources for something as insignificant as professional sports were Werder's sins.
Should we learn that Brad Johnson and Bobby Carpenter, or other players almost completely out of the loop of the team and its play, were the sources, then Werder's manipulation takes on a whole 'nother set of overtones: wilfully using the shield of anonymity to present a "blowup and breakdown of the lockerroom" case that wouldn't stand up if the sources were identified.
He didn't have to "make things up" to be wrong and unprofessional.