He announced his return to the team Friday on Instagram.
Russell, a senior, was serving a university suspension during the 2014-15 academic year and missed the 2014 season. The suspension stemmed from an academic fraud investigation that also resulted in suspensions to DaVaris Daniels, Eilar Hardy, Kendall Moore and Ishaq Williams.
The Irish enter 2015 loaded with experience on defense, and Russell adds even more. He started all 26 games as a freshman and a sophomore and was a preseason All-American candidate as a junior before the suspension was handed down in July. The 5-foot-11, 190-pound defensive back has 109 career tackles and three interceptions.
Williams, a senior defensive end, also will enroll in summer classes, his father Shaun told the South Bend (Ind.) Tribune. However, it is unclear whether Williams will be able to rejoin the team, the Tribune reported.
Daniels left Notre Dame early to pursue an NFL career, Hardy transferred to Bowling Green, and Moore's eligibility expired at the end of the 2014 season.