The centre-back comes up against Oxford City - the team he left in the summer to join the Hawks - with the Hoops heading to Westleigh Park for a National League South tussle on Saturday.
Former QPR and Torquay defender Oastler spent four seasons at Oxford City and skippered David Oldfield’s men last term.
But the 31-year-old insists his sole focus is making sure he helps Hawks deliver a fourth league victory in five - and then he can catch up with some familiar faces.
The Hawks captain said: 'It’s one of them, obviously I was there for four years, I know the club and know the people around the club.
‘It’ll be good to see a few people but I’m just concentrating on our game, really. I don’t really want to get too much with that side of it. I’m just focused on trying to get three points for us.
‘It’s going to be a very tough game. I know how the manager works having played for him. He’ll get them going.
‘I’ve said to a few of the boys at Havant, they’ll work their absolute socks off. He demands that and we’re going to have to match that.
‘There’ll be a few faces I’ll speak to after the game but before the game I’ll be fully focused on trying to do my job and helping the team out. I’m sure I’ll see a few friendly faces after the game.'
Hawks, who also have ex-Oxford City striker James Roberts in their ranks, have managed to overcome some early season injury issues to sit fourth in the National League South standings.
Oastler says a return of three wins from four is a solid start, but he stressed it's still very early days.
He added: 'We’ve started off okay for a team who have had injuries to key players; also, we’ve had 12 or 13 new players who have come in. We’re still learning about each other and we’re still getting them wins.’
There could be some familiar faces in the Oxford squad for Hawks fans.
Striker Joe Iaciofano left Westleigh Park in the summer to join City, who also boast ex-Hawks loanees Alfie Potter, Ben Dudzinski and Harvey Bradbury.
Iaciofano was prolific in pre-season, his tally including a 10-minute hat-trick against Banbury, and he started the first three games of the NL season, which were all dran.
He was on the bench when Oxford crushed Bath 5-1 and Bradbury and Elliot Benyon were up front when City lost their unbeaten tag last weekend, going down 3-1 at home to Maidstone.