Cincinnati Bengals sign K Marshall Koehn as insurance

The Cincinnati Bengals signed free agent kicker Marshall Koehn as insurance on Saturday, not taking a chance for Sunday's road game against the Jacksonville Jaguars with kicker Randy Bullock questionable due to a strained back.

In a corresponding move, the Bengals waived backup safety Derron Smith.

Koehn, 25, signed with Miami as a college free agent in 2016, playing in three of the Dolphins' preseason games before being waived. He converted both of his field-goal attempts and his lone extra-point attempt with the Dolphins.

Koehn was not with a team during the 2016 regular season and signed with the Minnesota Vikings during the offseason this year. He played in all four of the Vikings' preseason games, converting two of three field goals and five of six extra points. He was waived by the Vikings on final September cuts.

Koehn made 28 of 36 of his field goals and 92 of 96 of his extra points at the University of Iowa from 2012-15.

Smith has not played in the last four games with an ankle injury after performing largely on special teams in 31 of the previous 35 games.

Bullock strained his back Monday and missed practice Wednesday. He kicked on a limited basis Thursday and did not kick Friday.