With all due respect, but Vitesse aren't that much of big team in Holland (as you may have noticed when you searched their league-positions over the last couple of years). The Chelsea player they brought are destined to play first team football at Vitesse. Rajkovic played at Twente last year, wich became champions. So he certainly should get a starting place at Vitesse in terms of quality. A couple of media-platforms already reported that Delac should become the replacement of Velthuizen, so he will be the first choice keeper. And the one that remains is Matic, wich also should have a very good chance of making it into the first team. After all, you may presume, that is what Chelsea loaned him out for.