Luton Town forward McAtee, 24, older brother of Manchester City midfielder James, will provide another attacking option at the top of the pitch for the Reds after joining on loan for the 2023-24 campaign.
The striker, whose former clubs include Shrewsbury Town and Scunthorpe United, was part of the Grimsby Town squad who made history last term in reaching the quarter-finals of the FA Cup – becoming the first side from the fourth tier to reach that stage of the competition since 1990.
Ends to summer windows have rarely been straightforward in recent times for Barnsley, with supporters anxious that there are no unwanted developments this time around in terms of key exits.
Speaking at a fans’ forum late last week, Reds chairman Neerav Parekh said that the club were ‘definitely keeping’ influential duo Liam Kitching and Jordan Williams this window.
Kitching has been the subject of a failed bid from Coventry City – worth up to £3m.
Keeping his fingers crossed that the major theme on the final week will be inward, Collins, whose side make the Roses' trip to Wigan Athletic on Saturday, said: “That's fair to say that is what we are hoping the emphasis is on.
“But of course, there will be some guys that for their benefit and for ours, we might discuss about whether they move out for their development.
Collins, pictured, added: “I hope the emphasis is players coming in, but things change quickly in football.
“The chairman answered last week that he doesn't expect anybody (major) to leave, unless it is out of our control.
“We'll adjust accordingly if anything changes.
“I think there will be players who we are willing to discuss and if it's the right opportunity for their development and it's better for Barnsley, we will make those decisions.
“We will try and do what is best for not only the short-term but long-term for the player and club,” he added.