Walker is availible on a free transfer after negotiating a release from his Dunfermline contract before the transfer window closed. He left Saints in the summer of 2002, paying his own transfer fee as Dunfermline refused to stump up the cash. He was a vital part of our championship squad, but lost his way after this. He likes to get forward and scored a fair number of goals.
I'm not too keen to have him back, as he hasn't been great for the last few years. However, he is a left footed defender, and currently Laurie Ellis is the only left footed defensive player we have. If Walker plays, Ellis can then move to left wing due to the absence of Simon Lappin.
Walker is set to start against Brechin due to the fact Saints still have some injuries, despite claiming they'd all have cleared up. Mark Dempsie (surprise surprise) and Gus MacPherson are almost definitely out, whilst Kevin McGowne and Kirk Broadfoot are 50/50.
It is unlikely Walker will be back at Saints permanently due to the wage bill being full, however with these things you never know.
Story source: The Official St. Mirren Website