I had an interesting interaction with a reporter/writer that I was not familiar with until yesterday. His name is Tom Williams and he can be found on Twitter at @Tomwfootball. His original tweeted premise, on the occasion of Patrick Vieira's retirement as an active player, was spot on.
Measure of Vieira's impact: players like Abou Diaby mistakenly typecast as defensive midfielders just because they have a similar physique.less than a minute ago via web 
tomwfootball
There is an entire generation of lanky midfielders - mostly French or French-speaking West African - who have been labeled "next Vieira" while their managers, journalists and supporters attempt to push them into the "Vieira role", defined as box-to-box action with a heavy emphasis on the holding role. Not as holding-only as Makelele, but certainly far better and more focused on that role than someone like Pirlo or Alonso who is more deep-lying distributor.
As Mr. Williams indicates in his Tweet, it is a huge tribute to Vieira that the desire to find the next one of him caused managers to stop looking at a player's actual qualities and just assume that he should fit a certain mold. My response, which was perhaps a bit extreme but still valid at the core was that not only some players - most notably Yaya Toure - have been mis-categorized as holding midfielders by managers, the media, and supporters. There are also players, like Abou Diaby, who have been miscast as being better than they actually are because of the hope that they will eventually fulfill that "Next Vieira" promise.
@tomwfootball mistakenly typecast as DMs in the case of say Yaya Toure, miscast as top flight footballers period in the case of Diabyless than a minute ago via yoono 
nealjthurman
Mr. Williams didn't think very highly of my opinion of Diaby as being "miscast as a top flight player" which got me to thinking about what makes a good squad player. I think we'd all agree (even Mr. Williams) that Diaby hasn't shown enough that even a bottom half team would buy him with the intention of him being a regular starter. Between injury and lack of consistent production (either attacking or defending) he just isn't as good as midfielders currently starting in the Prem. Higher up the table he wouldn't be rated as of high enough quality. Farther down the table, his abilities might shine a bit more in comparison to current starters but his inability to stay on the field for more than a few matches at a time would make him a poor choice.
In an effort to re-examine my reply to Mr. Williams' Tweet, I started thinking about what makes a good squad player in an effort to determine whether I over-reacted in saying that Diaby has been miscast as a top flight player (at least in England). Here's what I came up with as far as constructing reserves:
