The Leeds United teenager has explained how he is developing in his early months at Elland Road.
Erwin is yet to play for the Leeds first-team, but he got two goals for the club’s under-21s this week and will be hoping that is a stepping stone to a potential Championship appearance sooner rather than later.
With Chris Wood, Mirco Antenucci and Souleymane Doukara all currently ahead of him in terms of striking options, Erwin will know he has a lot of hard work to do before he can consider challenging them.
But whatever the future brings, it is clear the 21-year-old is enjoying learning from Rosler and his Leeds coaches.
“I knew I wasn’t going to be part of the first-team straight away when I came in but I’m enjoying it,” he told BBC Radio Leeds. “I’m still only 21, developing under Rosler is pretty good for me.
“He says to get sharper, stronger; I’m doing programmes now with the fitness coach which hopefully means I’ll be up to scratch soon.”
Hopefully he will, because if he remains at Leeds – rather than heading out on loan – he could be exactly what Rosler needs when the going gets tough at the business-end of the campaign; an unknown element coming off the bench who has shown he has the scoring touch during his time at Motherwell in his homeland.