Cardinals safety Tony Jefferson makes the game-clinching interception against Baltimore last season.

Tony Jefferson was at the Cardinals' facility Monday for the first day of the team's voluntary offseason workout program.

The safety was allowed to take part because he signed his one-year tender offer as a restricted free agent, ending any possibility he might sign an offer sheet from another team and locking Jefferson in for the upcoming season.

The Cardinals other two tendered restricted free agents – wide receiver Jaron Brown and safety D.J. Swearinger – also signed their contracts.

Restricted free agents had until April 22 to sign an offer sheet from another team. There was a thought Jefferson, after receiving the "low" tender offer of $1.67 million for this season and with no draft pick compensation owed if another team signed him away, might get a long-term offer elsewhere. But he did not, and returns with a chance to reach unrestricted free agent status after the season.

Jefferson is expected to contend for a starting spot. Free-agent signee Tyvon Branch and Tyrann Mathieu, who is recovering from a torn ACL, should be the other two safeties on a defense that once again figures to use three in sub-packages often. Mathieu, rehabbing, isn't expected to take part in team activities before training camp. Mathieu has said he hopes to be ready by the open of camp in late July.

Jefferson was fourth on the team with 75 tackles in 2015, with two sacks and two interceptions – including a game-saving end zone grab against Baltimore and one returned for a touchdown in Chicago.

Swearinger, a former second-round pick who briefly was on the Cards' practice squad before being promoted to the active roster late last season, will also have a chance to get into the mix at safety.

Brown has been a key special teams player, and serves as depth on a loaded wide receiver corps. Last season, Brown had 11 receptions for 144 yards and a touchdown.