Why do players deteriorate?

[Salopian 1]

I am referring especially to the defence. It seems agreed that Drury is not the player he was, except in brief intervals. Shackell seems to be losing the qualitites he had, and it''s almost as much a "heart in mouth" moment when the ball goes near him as it is when it goes near Doherty, and Doherty himself, player of the year is now referred to by some as "Donkerty"None of these in age terms is "over the hill" as, say, Flem is, and Malky McKay at a higher level seems to survive without great pace.The one defender who seems to be improving is Colin, so why is he different?Is it the usual factor, - fear, or loss of confidence, - blast the ball anywhere in panic? Is it a collective fear or panic that was steadied when Dublin played there with reassurance? Do they lack individual control or skill on the ball?Several have pointed at the difference in Shackell''s performance when playing alongside Dublin compared with that alongside Doherty. Is it an inability to rely on Doherty being in position or being beaten that panics Shackell? Is it the big gap down the left, especially if Drury goes forward, that drags Shackell out of position?At Tamworth the defence was a shambles at times, with the fullbacks failing to close down attackers but merely shadowing them. Significantly it was Safri, closely followed by Etuhu, who almost blocked the Tamworth goal shot, but two of them can''t do all such work and be everywhere.I think that we need a change in personnel, a new right-sided centre back, or Dublin if we sign another striker, but they also need training to tighten up who does what and who covers what. We seem at danger to corner kicks and free kicks, and to opposing midfielders who arrive to support strikers. How many goals have we conceded this season to attempts like Tamworth''s, or to gift headers on the six yard line because somebody has not been marked? On second thoughts, we also need another goalkeeper!