Celtic boss Tony Mowbray has been looking hard at his defensive options ahead of Saturday's SPL clash against Dundee United at Celtic Park. With Glenn Loovens and Jos Hooiveld still injured and Darren O'Dea suspended the boss says that he is contemplating using Lee Naylor at centre-back Lee Naylor could be drafted into central defenceAndreas Hinkel looks set to return to Celtic's back line tomorrow but with Dutch pair Loovens and Hooiveld still out injured, and Darren O'Dea suspended after receiving his marching orders at Pittodrie last week, the manager has major defensive problems and very limited options for this vital match against a Dundee United side who smashed through our first choice defence twice in the last five minutes at Tannadice last November to win that game 2-1. Two rookies, 18-year-old Josh Thompson and 19-year-old Thomas Rogne, are the only natural central defenders available to boss Tony Mowbray but when asked if that would be the partnership to face United the manager was non-committal. "It might not be." he said. It might not be a centre-half. I might play Mark Wilson there, I might play Lee Naylor there. We will wait and see. You can play full-backs at centre-half no problem, it's been done many times, as long as they have a defensive mind and understand the danger.""It's not ideal when your three experienced centre-halves are not available." said Mowbray.,"But we will have some options. Every team has injuries or suspensions throughout the season, that's why you carry a squad and that's why you have players who can play in a few positions."The fact that Mowbray is even considering Lee Naylor and Mark Wilson as central-defensive options, two guys unable to command a regular slot in their own positions, graphically illustrates the folly of releasing our two most experienced defenders, McManus and Caldwell, before securing adequate replacements. Both had their critics and, if truth be told, most Celtic fans weren't particularly upset at the thought of losing either of them, but the unfolding scenario of having to perm any two from four - Thompson, Rogne, Wilson and Naylor - at the heart of our defence against United and, heaven forbid, the Huns at Ibrox next week, could have even their fiercest critics pining for 'Heid and Hoof'. There's no doubt that Mowbray has been unlucky with injuries in that vital area but more worrying for Celtic fans is the fact that two of the three missing central defenders, Loovens and O'Dea, have yet to convince the support that they're worthy of a starting slot whilst Jos Hooiveld is still an unknown quantity at this point. "Every football team has injuries and suspensions to deal with," said the manager. "That's why you carry a squad and not just a team of 12, 13 or 14 players. You have to have 22, 23 or 24 players. We brought Hooiveld in and his career is on the up. He's coming back, he's at the right age and he's experienced now. He can get the job done and you've seen his personality, he's a potential leader in the team. And Loovens has played for Celtic for a few seasons. He knows what is expected and what it takes to win games."They're both big losses for us." said Mowbray. "As Hinkel has been too. When we get them back, with the goals that we carry at the moment, then things will look bright. But right now we have to work hard with the players we have available. It doesn't change our philosophy of trying to be positive and win every game."