With the surprise announcement Friday that he had parted ways with defensive coordinator Don “Wink” Martindale, Ravens coach John Harbaugh created a major hole in his staff. Harbaugh has always hired from within when choosing his next coordinator, but he could also look to familiar faces outside the organization.

Here’s an early look at potential candidates:

Mike Macdonald

Harbaugh spoke of Macdonald, 34, as a future defensive coordinator when he served as a Ravens assistant from 2014 to 2020. Macdonald then proved he could excel in the role at the college level, working for Harbaugh’s brother, Jim, at Michigan. With Macdonald at the helm, the Wolverines held opponents to 17.4 points per game, eighth best in the country, and featured potential first-round draft picks Aidan Hutchinson and David Ojabo. Michigan had allowed 34.5 points per game the year before Macdonald arrived from Baltimore. He served as linebackers coach for the Ravens, earning praise for his work with individual players and on building communications across the defense. Macdonald’s future could hinge in part on Jim Harbaugh’s plans, with rumors swirling that the younger Harbaugh might be eyeing a return to the NFL.

Anthony Weaver

If Harbaugh looks to promote from within, Weaver, 41, would come with recent experience as an NFL coordinator. He led the Houston Texans’ defense in 2020 before joining the Ravens as run game coordinator and defensive line coach for last season. The Ravens led the league in run defense with Weaver supervising them in that area. The Texans struggled in his lone season as coordinator, ranking 30th in total defense and 27th in scoring defense. But Weaver built an excellent reputation coaching Houston’s defensive line from 2016 through 2020. Superstar defensive end J.J. Watt described him as an “incredible coach” and “great man.” Weaver played seven years in the NFL as a defensive lineman, the first four of those for the Ravens, who drafted him in the second round of the 2002 draft out of Notre Dame.

Chris Hewitt

Though Hewitt, 47, does not have experience as a defensive coordinator, he has coached the Ravens’ secondary since 2015 and has coordinated the team’s pass defense the last two seasons. The Ravens ranked last in pass defense in 2021, which could work against Hewitt despite his unit’s excellent track record in previous seasons. The secondary was decimated by injuries to starting cornerbacks Marlon Humphrey and Marcus Peters and starting safety DeShon Elliott but struggled to prevent explosive plays throughout the season. Hewitt has a long-standing relationship with Harbaugh, who coached him at the University of Cincinnati. He played three seasons as a defensive back for the New Orleans Saints and coached at Notre Dame and Rutgers before joining the Ravens staff in 2012. Harbaugh has praised Hewitt’s “no-nonsense” style, transferred over from his playing days.

Joe Cullen

Cullen, 54, served as defensive coordinator for the Jacksonville Jaguars in 2021 after spending the previous five seasons as defensive line coach for the Ravens. His status in Jacksonville is up in the air after the Jaguars fired coach Urban Meyer in December of his first season. The Jaguars ranked 20th in total defense and 28th in scoring defense under Cullen’s guidance, but they sprinkled in a few excellent performances, holding the Buffalo Bills to six points in a Week 9 upset and the Indianapolis Colts to 11 points in a season-closing victory. Despite a tough season in Jacksonville, leading defensive players said they hoped their plain-spoken coordinator would stick around. “I support him 100%,” linebacker Myles Jack told Jacksonville.com. “Our defense has made strides.” Cullen also earned the respect of his players in Baltimore. He had served as defensive line coach for four other NFL teams before he joined the Ravens in 2016, and his experience nurturing interior linemen could be appealing for a team that needs to rebuild its front.

Jim Leonhard

The former Ravens safety might be a wild-card candidate compared to some others, but he has built an excellent track record in five seasons as defensive coordinator for his alma mater, Wisconsin. The Badgers held opponents to 16.2 points per game, fourth best in the country, in 2021 and ranked in the top 10 the previous two seasons. Leonhard started 13 games for the Ravens in Harbaugh’s first season as coach and was known as a smart, versatile player over 10 NFL seasons. He has no pro coaching experience but was a defensive coordinator candidate for the Green Bay Packers last winter.