Not a grammarian, but I'll comment anyway. "Milton Smith" is an appositive, a term that further explains "the Chelsea centre-forward". Appositives are often set apart by commas from the rest of the sentence, but...
Sometimes the appositive and the word it identifies are so closely related that the comma can be omitted, as in "His wife Eleanor suddenly decided to open her own business." We could argue that the name "Eleanor" is not essential to the meaning of the sentence (assuming he has only one wife), and that would suggest that we can put commas both before and after the name (and that would, indeed, be correct). But "his wife" and "Eleanor" are so close that we can regard the entire phrase as one unit and leave out the commas. Source
the Chelsea centre-forward Milton Smith Chelsea centre-forward Milton Smith Chelsea's centre-forward, Milton Smith Chelsea's centre-forward Milton Smith Milton Smith, Chelsea's centre-forward Are they all correct?