This article is in decent shape, but it needs more work before it becomes a Good Article.
Is it well written?
A. The prose is clear and concise, and the spelling and grammar are correct:
In the Early career section, "Horsfield was born in Barnsley, South Yorkshire, the son and grandson of coal miners", can the names of his father and grandfather be included? Same section, "where a knee injury threatened his career", sounds very odd, might need to be re-written. In the Fulham section, this ---> "the player agreed to join First Division rivals Birmingham City", you need to be clear on who you are talking about.
Have found no source of parents' names. Reworded knee injury bit. Clarified to "Fulham's First Division rivals".
In the After football section, "On the 3rd of December 2008" ---> "On 3 December 2008", per here. Since his "personal life" section is small, you might want to combine the second sentence, of the section, with the first one, since its a related topic.
Already done, and cited; you must have caught the article between someone adding today's good news and me tidying it up.
A. It contains a list of all references (sources of information), presented in accordance with the layout style guideline:
B. Reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose):
It represents viewpoints fairly and without editorial bias, giving due weight to each:
In the Early career section, this ---> "where he turned professional in July 1992", sounds like POV and might need to be re-written. In the Birmingham City section, "In the starting eleven for the final against his boyhood heroes Liverpool", POV.
"Turned professional" just means he started to be paid for playing football as his main job. "Boyhood heroes" is a direct quote from Horsfield himself: see reference #26.