It was a busy transfer deadline day at Boundary Park on Monday.
Jonny Smith was the first arrival on Monday, joining on a season-long loan from Championship club Bristol City.
He was followed through the entrance by midfielder Filipe Morais, who returns for a second spell at the club after completing a season-long loan move from Crawley Town.
But experienced striker Chris O'Grady has ended his 13-month stay with the Latics, joining League One strugglers Bolton Wanderers.
Smith began his career at Wrexham, playing one game for the Welsh club before making the move to Bristol City.
He spent the 2017/18 campaign out on loan, making a significant impact at AFC Fylde, where he scored 10 goals in 47 appearances across all competitions.
Even at a relatively young age, the 22-year-old already has experience of helping a team gain promotion from League Two to League One. He contributed four goals in 36 games for Tranmere Rovers last term.
Smith will wear the number 26 for the Latics and will compete with the likes of former Manchester United and Burnley man Chris Eagles for a place in the team.
Morais returns to Boundary Park after seven years away. He joined in 2010 and scored eight goals in 68 appearances before departing for Stevenage in 2012.
The 33-year-old, who will be Oldham's new number eight, has garnered a wealth of EFL experience with the likes of Bradford City, Bolton Wanderers and Millwall.
Now that I have finally got up here and everything has been finalised....I’m delighted to say I have signed on loan back at @OfficialOAFC. I have still got lots of friends from my previous time at the club, so I can’t wait to start now and really excited to put the shirt on again pic.twitter.com/iQMy27e7Gv— Filipe Morais (@moraisfilipe20) September 2, 2019
Meanwhile, O'Grady rejoined Oldham in July 2018 and made 23 league appearances, scoring six times last season.
The 33-year-old also had a two-year spell with the Latics between 2008 and 2010, appearing 13 times.
Oldham said in a statement: "The club would like to thank Chris for his contribution at Oldham Athletic and wish him the best of luck in the future."
Just a couple of hours after his departure, O'Grady was confirmed as a Bolton Wanderers player, boosting the strikeforce of League One's bottom club.
The Latics currently sit 22nd in the fourth tier of English football, with just four points from their opening six league games.