Owings Mills, Md. — Forced to assess the 2017 season far sooner than anticipated, Ravens coach John Harbaugh acknowledged changes must be made for Baltimore to snap its three-year run missing the playoffs.

He will not, however, shuffle the coaching staff.

Harbaugh will fill the void left by the retirement of defensive coordinator Dean Pees, but said Thursday he will bring back offensive coordinator Marty Mornhinweg — the former Lions head coach from 2001-02 — and attempt to keep the rest of the staff intact unless “guys get opportunities to go somewhere and do some different things.”

Pees announced his retirement Monday, less than 24 hours after the Ravens (9-7) were bounced from the playoff chase with a 31-27 loss to Cincinnati.

The in-house contender for the coordinator job is Ravens linebackers coach Don Martindale. Chuck Pagano, fired as head coach of the Indianapolis Colts on Monday and Baltimore’s defensive coordinator in 2011, is also among those being considered.

The offense needs help. Harbaugh lauded the performance of quarterback Joe Flacco , who rebounded from a back injury to come on strong during the Ravens’ late-season playoff push.

But the coach was unrelenting in his assessment of the wide receivers, noting that there were too many dropped passes and far too few big plays from a unit built around veterans Mike Wallace and Jeremy Maclin and featuring 2015 draft pick Breshad Perriman, who is thus far a first-round bust. Baltimore ranked 29th in net yards passing per game (189.4).

“That’s an area we’ve got to look at really hard,” said Harbaugh, the brother of Michigan head coach Jim Harbaugh. “The passing game wasn’t where it needed to be.”

Tight end Benjamin Watson led the team with 61 catches and six touchdowns. Wallace and Maclin combined for only seven scores, and Baltimore had only five catches of at least 40 yards.

“We want to get playmakers. That’s something that we need,” Harbaugh said. “We’re going to add players. It’s not to say that we can’t add some players through free agency. That’s the way that the salary cap works. The draft will be the major part of it.”

Mornhinweg, who went 5-27 in two seasons as the Lions’ head coach, has been on the Ravens’ staff since 2015.