Borja spoke to the local media on Tuesday.
He stated: "It was not what I had hoped for. I was really excited to go there after the seasons I had in Spain. I arrived as the most expensive signing in Swansea's history (€18m), and at no point did they give me the chance to show what I could do. Right now, I'm keen to feel important to a team again and have a good season."
The striker also remarked: "I arrived with an arm injury that I had picked up at Atlético, and just when I was recovering I had a small problem with my quadriceps. I recovered from that and was able to play a couple of games, but then they [Swansea] fired the manager who had brought me in (Francesco Guidolin).
"It was difficult after that because the manager who came in (Bob Bradley) drove the team mad. He made lots of changes and we didn't know what we were trying to do. In the end, with the arrival of Paul Clement, the team settled and we managed to stay up."