Cardiff will allow long-serving Kevin McNaughton to leave this summer along with Danny Gabbidon and Nicky Maynard.
Highly-rated Atletico Madrid midfielder Saul Niguez has signed a new five-year contract.
Manager Brian McDermott has defended Jimmy Kebe's attack on Reading's transfer policy under owner Anton Zingarevich as evidence of his passion for the club.
Kebe responded to Monday's 5-2 home defeat by Arsenal, a result that leaves them rooted to the foot of the Barclays Premier League, by criticising the lack of signings made during the summer.
"We are in big trouble. We should have bought some decent players in the transfer window. We are a good Championship team trying to compete in the Premier League, that's it," Kebe said.
Less than £5million was spent during the summer and the indication is that McDermott will be given a similar budget to sign the two or three players with top-flight experience that he wants.
McDermott admitted last week that Reading had misjudged their transfer policy since winning last season's npower Championship and refused to condemn Kebe's comments.
"What it shows is that Jimmy Kebe, like every other player here, cares. He really cares, we all care," McDermott said.
"Jimmy cared last season when he signed a new contract. He wanted the club to get promoted, which we did.
"Jimmy Kebe loves his football, he loves this club, he loves working for us. He's very much part of what we're trying to do here.
"The owner cares, the chairman cares, I care, the fans care, Jimmy Kebe cares. All our players want the club to do well, first and foremost.
"Let's hope a 'good Championship side' can get the points we need to get to wherever we need to get to.
"I'd like to think that we have enough decent players and that we can get the points we need. Time will tell on that.
"The summer's gone and there's nothing we can do to change what happened. All we can do is affect what happens now."
McDermott reiterated that Reading will prioritise sound financial practice over high-risk spending to ensure the club remains free of debt.
But if they fail to strengthen sufficiently next month then the Championship surely beckons with no Premier League club escaping relegation having accumulated only nine points after 17 games.
Discussions over the budget have begun with Zingarevich and director of football Nicky Hammond and McDermott is hopeful there will be transfer activity next month.
"Our current squad could be strong enough to get us out of trouble, we will see in May," he said. "We'll see if we can add players in January - sometimes you add a couple of players and that freshens things up.
"It helps to make the rest of the squad better as well, so that could definitely be a good thing for us.
"I honestly thought the squad in the summer would do okay, but we'll have to find a way of getting results. We can do it, but I've always had that view."