He told BBC Sussex: "The manager Steve Evans rang me and I liked the sound of what I heard.
"They're enthusiastic, optimistic and looking to go one better than last season. The squad they're building is capable of doing that."
He added: "There's still a wide range of people they're considering and they seem to be pretty screwed-on about what they're doing.
"This offer was what I wanted and I got the right vibes from everyone involved in the club."
Evans told the club website: "Danny has impressed me every time I have seen him play. He is very quick and that is a major asset for any central defender.
"It's great news but there is a lot more work to be done to get us ready for the challenges we will face next season."
Source: BBC Sport
Source: BBC Sport