"He (Pearson) didn't want me to go - that's the reason the loan took so long to go through," Campbell told the Derby Telegraph. "But I wanted to come here and play because I've not really been getting a look-in at Leicester and it's been tough.
"I'm 28 and I need to be playing games week-in, week-out, so that's the main reason I came here."
Campbell also revealed he would be open to extending his initial month-long stay at Derby if he was playing regularly.
"I'm happy to be here and we'll see what happens at the end of it. If things are going well and I'm playing and scoring goals, we will see where that takes us."