Although Saints are looking to promote the academy players where possible, Cork's signing is a welcome boost after the departure of Andrew Davies.
At 19 he fits in well with Saints' youth policy and given Chelsea's continual acquisition of global stars, he may indeed have a longer term future at Saints beyond his initial loan until New Year's Day.
The England U19 captain, Cork was Scunthorpe's player of the season on loan there last season and comes with an impressive reputation. He can play across the back line and even as a holding midfielder, adding valuable depth to a thin-looking back line.
Perry is unlikely to remain fit all season at 36, Svensson is still finding his way back to fitness after so long out, Thomas is out of favour and Lancashire remains very inexperienced. Outside the central defenders Saints have no real recognised full back although both James and Surman are growing into the role, with Mills and Hatch again very inexperienced backup.
Cork can push for a staring place and offer valuable cover. Chelsea will certainly be expecting him to play games and a long season and small squad will give him the opportunity to do exactly that.