Keates, who only has one fit central defender at his disposal is known to be targeting at least two defenders before the Transfer Window closes in a two weeks, but is also aware that there are gaps in other areas.
The manager, who was dealt a major injury blow earlier in the pre-season campaign as highly-rated defender Kory Roberts suffered a double leg break during the recent clash with Stoke City, also revealed that he has some loan deals lined up if he can't secure permanent signings.
Speaking at Tuesday evening's 'Meet the Manager' event, Dean confirmed; "I want there to be a minimum of three additions but I’m hopeful of four. The centre-half needs addressing, it will be addressed in the next few days. I will be looking at centre mid over the coming days and also a central striker. I’m not going to add for the sake it. Have we got enough strength in depth? No.
"I want to sign our own players but if that doesn’t happen I’ve got some more than capable loans – good under-23 players who are pushing for a place in the first team at their clubs. But ideally I’d like to bring in our own players."