The 49ers on Wednesday signed safety Antone Exum Jr. after another safety, J.J. Wilcox, turned them down a day earlier.

Wilcox, a five-year veteran, reportedly was ready to sign with the team when he had a change of heart and decided to join the New York Jets instead. One of the Jets' reserve safeties, Rontez Miles, will miss up to four months after having knee surgery and Wilcox may have figured he stood a better chance of landing a permanent spot on that roster than the 49ers'.

The 49ers' starter at strong safety is Jaquiski Tartt, but there's currently a dearth of backups since draft pick Marcell Harris and veterans Don Jones and Chanceller James are recovering from major injuries suffered last year.

Exum, meanwhile, appeared in two games for San Francisco with one start last season after injuries struck the team's secondary, especially free safety. The 27-year-old former sixth-round pick spent the first three and a half seasons of his career with the Minnesota Vikings, whom the 49ers will face in their regular season opener.