The Baltimore Ravens' offensive line underwent further changes on Wednesday, when they traded center Jeremy Zuttah to the San Francisco 49ers.

The Ravens have now parted ways with two offensive linemen who were three-year starters for them. Last week, right tackle Rick Wagner signed a five-year, $47.5 million deal with the Detroit Lions.

It's two different reasons why the Ravens need to replace their starting center and right tackle. Baltimore decided to let go of Zuttah because he was too often overpowered inside, and the Ravens weren't close to keeping Wagner after he received a deal that averaged $9.5 million per season (the second-highest ever for a right tackle).

These moves are in addition to the switch at offensive line coach. Juan Castillo, who spent four seasons coaching the offensive line, moved on to Buffalo and Joe D’Alessandris was hired to replace him.

The only mainstays were Pro Bowl right guard Marshal Yanda, left tackle Ronnie Stanley and left guard Alex Lewis.

For right now, the Ravens can pencil in moving guard John Urschel to center, although that appears to be a fallback option. The market for centers was never great, and Nick Mangold remains the best available. Baltimore could decide to look in the draft, which doesn't have many great centers, and look to convert an athletic guard to that spot.

Unlike the center position, the Ravens don't have an experienced backup on the roster to plug in at right tackle. Baltimore can find a veteran in free agency like Ryan Clady (who would have to go from left to right tackle) or Austin Pasztor.

The Ravens ranked as the ninth-best offensive line by Pro Football Focus last season. But this was a unit that struggled at times.

Baltimore running backs averaged 2.17 yards before first contact, which was the seventh-worst in the NFL last season. Quarterback Joe Flacco was pressured on 183 dropbacks, which were the seventh-most in the league.

What the Ravens lose the most are two players who gutted it out on the field. Zuttah tied for the most snaps on the team, and Wagner ranked third on offense.

The needs on offense continue to pile up for Baltimore. The Ravens have now lost four starters (Zuttah, Wagner, fullback Kyle Juszczyk and retired receiver Steve Smith Sr.) and they have yet to sign any of their replacements.

It could be a much different look for the entire offense as well as its line.