Take one of San Francisco's pending 15 unrestricted free agents off its "to-consider" list.
Special teams ace/safety Bubba Ventrone, 32, has retired and is returning to his original NFL team as a special teams assistant, the New England Patriots announced on Tuesday.
Ventrone, who first signed with New England as a rookie free agent out of Villanova in 2005, was also with the New York Jets in 2007, and played for the Cleveland Browns from 2009 through 2012, before coming to San Francisco in 2013.
With the Niners in 2013, he was second in special-teams tackles with 15. He returned to Santa Clara on Oct. 8, 2014, played in eight games and had three special teams tackles before a groin injury ended his season in December.
Ventrone retires with 54 special teams tackles, two special teams fumble recoveries and four kick returns.
Following are the Niners' pending UFAs:
QB Josh Johnson
RB Frank Gore
LG Mike Iupati
LB Dan Skuta
CB Perrish Cox
CB Chris Cook