Fight Matrix, June 2010
Wow, he was indeed at 57. But looking at the date when the rankings were published, he had lost to Bisping, been suspended for a year, then lost to Rosholt, though he had beaten Jay Silva in his last fight. Still, he was at a pretty low point. Fight Matrix hadn't been updated with his win over Aaron Simpson, which would have moved him up quite a bit. So, it's kind of a fluke that he was still ranked that low.
By the time the next rankings were published, and his wins over Simpson and Akiyama were taken into account, Leben was back up to 13.