Safety Darren Sharper was near the top of his game last season, so it was strange to see him linger on the free-agent market for quite a long time. He signed a one-year deal to remain with the Saints on Monday and details emerged as to why he spent so much time without a contract. Sharper underwent microfracture knee surgery, according to a league source. He was said to have had arthroscopic knee surgery, but microfracture surgery is much more severe and places in doubt in just how much Sharper will be able to work out this summer.