The Raiders have signed to two veterans to fortify a depleted defense.

They formally announced the additions of safety D.J. Swearinger and defensive end Dion Jordon on Saturday, hoping these imports can fill in for fallen Raiders.

Karl Joseph was placed on injured reserve Saturday in one corresponding move, lost for the season after injuring his foot while securing a 26-24 win over the Los Angeles Chargers with a last-second interception.

The Raiders played down two defensive ends Thursday night with Josh Mauro out temporarily and Arden Key done for the year with a broken foot. He had surgery and was formally placed on IR Thursday. Linebacker Quentin Polling was promoted from the practice squad for that game and waived Saturday to make room for Jordan.

Joseph’s loss is significant. He played virtually every snap this season, coming into his own in his second season under Paul Guenther. Joseph was a solid box safety and run defender, someone who could also play deep. That was clear when he closed out each game of this two-game Raiders winning streak.

He knocked down a Matt Stafford pass that beat the Detroit Lions on Sunday and intercepted Rivers on Thursday to end a Chargers comeback attempt.

Joseph finishes his season with 48 tackles -- including a career-high four for a loss -- as well as four passes defensed and an interception that could be his last act as a Raider. The 2016 first-round pick is set for unrestricted free agency this offseason after the Raiders decided against picking up his fifth-year option.

The 26-year-old has been a quality starter throughout his career, but the Raiders were considering trading him last year and could go in a different direction at his position. Time will tell on that front, but we know for certain he was a valued contributor this season starting to find his professional footing as a hard hitter and a cover man.

Curtis Riley has been the team’s third safety, but it’s likely Swearinger could step in and start if he quickly picks up the defensive system.

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Meanwhile, Jordan is a low-risk signing with a possibly high reward. The 2013 No. 4 overall NFL draft pick has been a bust, due to ineffectiveness and issues with substances of abuse. Jordan has been suspended multiple times since turning pro, missing four games in 2014 and all 16 in 2015. iJordan was suspended for a third time this May for using Adderall, missing the first 10 weeks of the season.

The 26-year-old reportedly is sober and in great shape, with the raw talent to be a quality contributor the Raiders desperately need up front.