After Gary Caldwell joined Wigan and Stephen McManus moved on loan to Middlesbrough during the transfer window, Dutchman Loovens was left as the most senior central defender at the Parkhead club.[LNB]With Darren O'Dea and Jos Hooiveld injured, and new signing Thomas Rogne yet to make his debut, Loovens has had to nurse along 18-year-old rookie Josh Thompson in recent games.[LNB]Ahead of Wednesday night's Clydesdale Bank Premier League clash with Hearts, the former Cardiff stopper revealed that all things being equal he would consider himself a first pick - and is happy to take on the responsibility.[LNB]"I have to be at my best and, if I am, then it us up to the manager," Loovens said.[LNB]"But yes, if I am fit and playing well, I feel I have to play.[LNB]"I have played with five or six different players at the back and you have to deal with it.[LNB]"There are a few defenders injured so other players have to stand up and get on with the job.[LNB]"Josh is young and he has to learn a lot but he is doing a great job.[LNB]"I'm sure he is going to be a great player and it our job to help him."[LNB]Manager Tony Mowbray will consider giving Rogne his debut tonight but will have no problems continuing with Thompson.[LNB]"Fitness-wise, Rogne has probably done enough now," he said.[LNB]"I have no fears for Josh Thompson.[LNB]"He has done a very good job.[LNB]"He's only 18, a young boy, and I have been impressed with him.[LNB]"Sometimes you give people an opportunity and they grab it and Josh has done that."[LNB]Someone hoping to do the same tonight is Hearts new boy Ryan Stevenson.[LNB]The 25-year-old midfielder, who joined from Ayr last week, could make his debut at Parkhead,[LNB]"The pressure side of it doesn't faze me - there are people fighting wars," he said.[LNB]"To play at Parkhead in front of 65,000, you can't really ask for anything more."[LNB]Stevenson revealed how Hearts, St Johnstone and St Mirren were fighting for his signature before the transfer window closed last Monday but he actually feared ending up at none of them.[LNB]"I was to-ing and fro-ing between the three of them," he said.[LNB]"On Monday, things weren't quite worked out between Hearts and Ayr so it was still St Johnstone until quite late in the afternoon.[LNB]"You're thinking, 'Where am I going to be on Monday?'.[LNB]"We were training Monday night at Ayr and I'm thinking, 'If all this falls through, I'm back at Ayr', which would have been a disaster for myself.[LNB]"I thought if I woke up on Tuesday morning and I was anywhere else, I would regret it.[LNB]"I would look back and say, 'I had a chance to come to Hearts and for whatever reason it never happened'.[LNB]"I would have been devastated."[LNB][LNB][LNB] Celtic v Hearts. Click here to bet.