OWINGS MILLS –The Baltimore Ravens are concerned enough about veteran center Matt Birk due to a problematic left knee that they signed former Washington Redskins center Casey Rabach to a two-year contract.

The six-time Pro Bowl blocker underwent a magnetic resonance imaging exam and could need to have arthroscopic surgery after needing to have fluid drained from his knee nearly each week last season.

A former Ravens third-round draft pick, Rabach provides insurance in case Birk is sidelined for a long time or unable to play this season. Rabach is also capable of being the swing interior player at center and both guard spots, role former Ravens lineman Chris Chester held until he signed with the Redskins last week.

“That’s exciting,” offensive coordinator Cam Cameron said regarding Rabach. “He’s had a heck of a career. That gives us some depth at center. We will see how things have turned out with Matt Birk.”

Rabach , 33, played behind Mike Flynn for the majority of his career in Baltimore, signing with the Redskins when Baltimore opted to retain Flynn despite Rabach being younger and more athletic.

Birk, 35, considered retiring during the offseason, but told Ravens24x7.com earlier this offseason that he felt good enough to play one more season. He’s due a $3 million base salary in the final year of his contract and hasn’t missed a game in six years. He hasn’t practiced the past two days.

“My desire is definitely there,” said Birk, who has also battled neck pain. “I want to do it again and contribute. We love the organization and we love the team. I’m feeling pretty good.”

The Ravens have several other centers on the roster, including a trio of undrafted rookies: Ryan Bartholomew, Tim Barnes and Justin Boren.

Now, Rabach enters the equation.

“Casey has been here, so it’s just like he’s coming home,” outside linebacker Terrell Suggs said. “When I first got here, he was here and he kind of toughened me up, slapped me around a little bit. Now that he’s in the later stages of his career, I look forward to doing it to him a little bit.”

GRUBBS GETTING INTO THE GROOVE: After undergoing ankle surgery this offseason to remove bone spurs, offensive guard Ben Grubbs has practiced the past few days without incident after passing his physical.

He’s dealing with some soreness, but nothing serious.

“It’s going to be some trying times any time you have surgery,” Grubbs said. “You have to take steps as far as getting back into the groove of things. The things that I’m experiencing right now, it’s expected. I’m not really worried about it. Right now, you expect the soreness.”

And Grubbs is also getting acclimated to football again as he gets back to work for the first time since January.

“The first day, I was feeling a little rusty,” Grubbs said. “That’s how it will roll.”

REED STILL SIDELINED: Wide receiver David Reed underwent surgery this offseason to repair a torn ligament in his left wrist suffered last year when he led the NFL in kickoff return average as a rookie.

Reed remains on the physically unable to perform list, but expects to return as soon as next week.

“It’s strong, it’s real strong,” Reed said. “I’ll be back soon, probably like a week.”

Last year, Reed averaged 29.3 yards per kickoff return and set a franchise record when he ran back a kickoff 103 yards for a touchdown during an overtime win over the Houston Texans.

“I had surgery, and I’ve just been running mostly,” Reed said. “I don’t do a lot of working out. I feel good, though.”

IMPRESSED WITH KINDLE: Affirming that outside linebacker Sergio Kindle remains on the right path after missing his entire rookie season with a skull fracture, defensive coordinator Chuck Pagano is pleased with the former second-round draft pick’s progression.

Most importantly, Kindle hasn’t had any medical setbacks, has been learning the defense and isn’t hesitant to hit.

“I can tell you that he’s picking things up,” Pagano said. “He has not shied away from any contact. There has not been one time. I don’t think anybody should talk about this, that or the other. We’re just coaching the kid. He’s showing up every day.

“He’s at every meeting. He’s taking notes. He’s learning. And he’s way ahead of where I thought he’d be. So, knock on wood if he keeps progressing like he’s progressing, we’ll find a role for him obviously.”

FREE AGENCY UPDATE: The Ravens continue to stay in touch with San Diego Chargers free agent wide receiver Malcom Floyd, who played for Cameron for three seasons in San Diego.

Other suitors for Floyd include the Minnesota Vikings and the Arizona Cardinals.

The Ravens also have the option of bringing back Derrick Mason after cutting him recently.

 Floyd is a 6-foot-5 target who caught 37 passes for six touchdowns last season.

Meanwhile, the Ravens are intrigued by New York Giants defensive end Osi Umenyiora.

The Giants were asking for a first-round draft pick in exchange for the disgruntled pass rusher.  Now, that price has dropped to a second-round draft pick He was granted permission to explore trade options.

Should the Ravens be able to sign franchise defensive tackle Haloti Ngata to a new contract they would have the salary-cap space to sign Umenyiora to a new contract.

The Ravens recorded a franchise-worst 27 sacks last season. Umenyiora registered 11 ½ sacks last year.

Do they need help in the pass rush?

“Any great player around the league can always be an addition,” Suggs said. “But we have great pass rushers on this team. You guys just don’t know that because they do all the dirty work so that other guys can get sacks.”

INJURY UPDATES: First-round cornerback Jimmy Smith (groin) and second-round wide receiver Torrey Smith (hamstring) didn’t practice.

“I’m perfectly fine,” Torrey Smith said with a smile. “I’ll probably be practicing soon.”

Jimmy Smith posted on his Twitter account that his injury is minor.

Cornerback Domonique Foxworth, who has complained of soreness in his surgically-repaired knee, didn’t practice.

The Ravens’ depth at receiver has dwindled with Smith and veteran James Hardy (hamstring) both not practicing.

The Ravens have lined up with Anquan Boldin opposite Justin Harper and Brandon Jones.

Cameron expressed hope that Smith and Hardy might practice today.

“I hope so,” he said. “They have had a day off, a good solid day off. They have some hamstring tightness, maybe some hamstring weakness, but I don’t think anybody really pulled a hamstring.”

QUICK HITS: The Ravens waived rookie offensive tackle Alex Sodot, a 6-foot-8, 316-pounder from UTEP. .. Cameron joined the chorus of team officials, coaches and players impressed with rookie tackle Jah Reid. “He had his best day,” Cameron said. “It’s overwhelming, but I think he settled in. I saw a little difference. Things weren’t as confusing. It looked like he corrected some mistakes, and that is a great sign when young guys start correcting mistakes this early on.” … Quarterback Joe Flacco has gained roughly 10 pounds of muscle and Cameron thinks it’s beneficial. “Joe has come back in great shape,” Cameron said. “He has put on 10 pounds, which was his choice, and you really can’t notice it, other than seeing added strength. He is in tremendous shape. He is as sharp starting off as I have ever seen him. We’re at the best starting point with him going into the season than we have been since he has been here. I haven’t flinched on anything that I have believed about Joe Flacco since the first day I saw him.. I think he is a great quarterback. I think he is going to continue to grow.”