The 24-year-old, who joined in a £2m-plus deal from Sporting Gijon, had seen an alternative move to Getafe fall through but now the former Hibernian boss is keen to see him in the Hoops shirt.
"He's 6' 1" so he's different from the ones we have," Collins said.
"He's good in the air and attacks crosses so he gives us another option.
"His goal scoring record is very good as his stats will tell you and that includes creating goals as well.
"Again, it's competition for places at the top of the pitch and that's what we want."
Scepovic was Celtic's sixth summer recruit following the arrivals of Craig Gordon on a free and Inge Berget, Jason Denayer, Mubarak Wakaso and Aleksandar Tonev on loan deals, with the latter arriving with an injury.
Collins is looking forward to having the whole squad fit and available for selection.
He said: "We have signed a lot of new players now and the majority on loan, and they are all getting fitter.
"Once we have got Tonev and Wakaso - who is away on international duty - back, they will give us pace in the wider areas.
"We now have competition for places. Scott Brown also is coming back (from a hamstring injury) and he's hugely important on the pitch, not only with the ball at his feet but driving the team forward.
"James Forrest has been unlucky with injuries and he's now back running and once we get everyone back, then there will be serious competition for places."