The arrests came after an investigation by The Sun on Sunday newspaper.
Blackburn says on its website it will not comment further because this is an ongoing legal matter. The club plays in the second-tier League Championship, one step below the Premier League.
The 32-year-old Campbell has previously played in the Premier League for Birmingham, Blackpool and Queens Park Rangers.
Another investigation last month, by the Daily Telegraph, led to two players from the sixth tier being charged with conspiring to fix matches.
- Sports & Recreation