Weddle moved back to free safety after the Baltimore Ravens signed free agent strong safety Tony Jefferson. Weddle and Jefferson were officially named the starters to begin the season. In Week 4, Weddle recorded a season-high eight combined tackles, two pass deflections, and an interception in the Ravens' 26–9 loss to the Pittsburgh Steelers. On December 3, 2017, Weddle made three combined tackles, a pass deflection, recorded a strip/sack, and returned an interception for a touchdown during a 44–20 victory against the Detroit Lions in Week 13. He returned an interception by quarterback Jake Rudock for a 45-yard touchdown in the fourth quarter and recorded a strip/sack on Matthew Stafford that was recovered by teammate Willie Henry in the second quarter. His pick six became the fourth of his career and his performance earned him AFC Defensive Player of the Week. On December 19, 2017, it was announced that Weddle was voted to the 2018 Pro Bowl. He completed the season with 63 combined tackles (49 solo), eight passes defensed, six interceptions, a sack, forced fumble, and touchdown in 16 games and 16 starts. Pro Football Focus gave Weddle an overall grade of 82.4, which ranked him 24th among all qualified safeties in 2017.