ZAK Whitbread knows he facing a tough battle to keep his place in the Derby County side.
Whitbread and Ryan Shotton have each played two of the past four matches at centre-half, alongside skipper Richard Keogh.
Their chance arose due to the suspension and then injury lay-off of Jake Buxton.
Buxton is now back in training and due to feature in a private friendly against Burnley tomorrow.
Assuming Keogh recovers from the slight hamstring strain he suffered on international duty with the Republic of Ireland, there could be four players competing for two positions ahead of Saturday's Championship match at Reading.
Steve McClaren's men have not conceded a goal in their past four games.
Whitbread partnered Keogh in the heart of the defence in the goalless draw against Millwall last time out and the 2-0 win at Bolton.
Shotton took his place, though, for the Capital One Cup tie against Reading and the League victory over Bournemouth.
"We've got a tremendous squad here and Ryan has come in every time and produced," said Whitbread.
"It's a squad game and we need all those players."
Whitbread accepts that nobody in the team is guaranteed a starting spot.
"There wasn't much said to me (after he was left out against Bournemouth)," he said.
"We're just lucky we've got players who can come in and step up.
"We've got options there. It's probably not the norm but there have been a lot of games and fresh legs coming in is always a positive.
"It's not something I'm too concerned about.
"The shirt is never anyone's. It's there for everyone to be fighting for, so you know you've got to be on your toes every time you come in, otherwise there are plenty of others who can come in and perform at a high level."
Whitbread was on loan at play-off finalists Derby last season and made the move permanent in the summer when his contract expired at Leicester City.
He has made only 10 appearances for the club so far, having been hampered by a calf injury soon after first arriving last term, but has started four of the Rams' last six matches.
"It was unfortunate," he said. "I was fit for most of last season – there were only a few weeks that I was out.
"That's always frustrating but, the rest of the time, I was patient and it was a pleasure being around the squad.
"It was an amazing journey, which in the end, wasn't quite to be."
Now he has had more of a taste of first-team action, the American-born 30-year-old will be doing his utmost to keep the shirt.
"It's great to be playing games – that's what it's all about for me," added the former Norwich City man.
"As long as the lads are getting results, picking up points and I'm a part of it, great.
"I've got to do everything I can to keep the shirt now."
