49ers sign ex-Dolphins DT Earl Mitchell

In the first significant signing of general manager John Lynch's tenure, the 49ers agreed to terms Friday with former Dolphins defensive tackle Earl Mitchell. Last year, the 49ers set an NFL record by allowing 100-yard rushers in seven straight games and surrendered the sixth-most rushing yards (2,654) since 1990. Last year, Mitchell suffered a calf injury, but the Dolphins activated him from injured reserve to play in their final nine games. Niners defensive line coach Jeff Zgonina was a defensive assistant with the Texans when Mitchell was there in 2013. The 49ers' poor run defense last year did get a boost as nose tackle Glenn Dorsey gradually returned to form after suffering a torn anterior cruciate ligament in November 2015. Carter, 5-foot-8 and 190 pounds, was a first-team FCS All-American after a senior season that included 1,321 yards and 17 touchdowns. The 49ers were awarded a compensatory draft pick, the No. 37 selection in the fourth round, in the wake of free agent offensive lineman Alex Boone signing with Minnesota last season.