Aston Villa manager David O'Leary is hoping to get a clearer idea today as to whether captain Olof Mellberg will be fit for Sunday's Second City derby.

The Swede has missed Villa's last three games with an untimely hamstring injury but O'Leary has also made it quite clear that, if Mellberg cannot play, he will have no hesitation in turning once again to young stand-in Gary Cahill.

The England Under-20 international turned in a hearteningly solid display to help earn a clean sheet on his full Premiership debut against West Bromwich Albion on Sunday.

O'Leary is confident that he can make it a derby double by doing the same against Birmingham City and the muscular presence of Emile Heskey.

"I'm 95 per cent that Olof's going to be fit," O'Leary said. "In the end, it has to come down to the player himself but if we did have to go into the game without Mellberg, I'd have no fears for Cahill.

"In fact, I'd have no fears for any of the young lads. I was a bit scared putting so many of them in together last week against such an experienced side, knowing there was the chance they might go into their shell, but they knew the crowd was with them and we'll need that again."

Although it was a first Premiership start for Cahill, Gabriel Agbonlahor and fellow teenager Craig Gardner had already made their first league starts and were part of a very inexperienced, injury-ravaged Villa side that went down 4-1 at Everton last month. But O'Leary says that suffering such a grilling will have helped them last Sunday.

"They're certainly the better for the experience of having come through Goodison,"

he said. "There was that little bit of 'What's going on?' about them that day, but they've come out of it the other side really well. It's not nice but it's good experience."

Villa's stand-in skipper on Sunday, in the absence of Mellberg and Gareth Barry, was Gavin McCann. He says that the young players coped all the better last weekend, having had to come into a struggling side.

"When you chuck a lad in who's done well, it's easier in a team that's going well," McCann said. "But to put three or four in at once makes it even tougher.

"They know each other's game well from playing in the reserves week in, week out, but the Premiership's a bit different from the ressies.

"The game up at Everton was one that could have gone either way, a good performance or us getting battered. But sometimes it's the only way you get a chance and, although it was a big ask for them again on Sunday, all the lads have come in and did well.

"Gabby had a good home debut, Craig Gardner came on for Lee Hendrie and wasn't overawed and Gaz Cahill did very well. In a way, he needed a chance like that. He knows it's only one game, but he's shown he can survive at that level of football."

O'Leary also still has worries over the knee injury that kept Barry out on Sunday and the foot injury suffered by Lee Hendrie. Although a re-energised, James Milner looks certain to bounce straight back in after six games out with a virus, during which he has been badly missed, Hendrie is battling to be fit.

As for Barry, though, O'Leary remains hopeful. "He looked great in training," the manager said. "From what I've seen out there, he looks available for Sunday, but we won't really know until he comes in tomorrow."