The Senators' official Twitter feed revealed that defenseman Erik Karlsson will be out indefinitely after suffering an Achilles laceration against Pittsburgh in mid-February:

Update on Karlsson: Erik suffered a laceration to his left achilles, which will require surgery to repair. He will be out indefinitely.

— Ottawa Senators (@NHL_Sens) February 14, 2013

UPDATE: Thursday, April 25 at 11:55 a.m. ET by Sam Westmoreland

For the first time since February, Erik Karlsson is going to be on the ice for the Senators. According to the team's official Twitter feed, the talented defender will make his return in Thursday night's game against the Capitals. 

Erik Karlsson will play tonight against the Washington Capitals. #TheReturn

— Ottawa Senators (@NHL_Sens) April 25, 2013

The defenseman also spoke out of his return to the lineup on his personal Twitter account.

BOOM.! FINALLY.! Back in the line up tonight. #soFHappy #cantwait #lalala

— Erik Karlsson (@ErikKarlsson65) April 25, 2013

---End of update---

UPDATE: Wednesday, Apr. 24, at 11:04 a.m. ET by Brandon Galvin

Exciting news for Ottawa fans as Erik Karlsson is expected to return as soon as tomorrow, according to Ottawa Sun's Bruce Garrioch.

Karlsson takaing a regular shift with Methot. Would appear he makes his return tomorrow. #sens

— Bruce Garrioch (@SunGarrioch) April 24, 2013

---End of update---

UPDATE: Friday, April 19, at 1:25 p.m. ET by Sam Westmoreland

It's been a while since we had anything resembling news, good or bad, on Erik Karlsson, but the supremely talented young defenseman has finally been cleared for contact, according to the team's official site. 

Per that report: 

"It's nice to be back on the ice," Karlsson told reporters after practicing with the team Friday. "It's been a while. It was a good thing to do,"

It was the first time Karlsson skated with the team since undergoing surgery to repair a 70-percent tear in the Achilles tendon in his left leg Feb. 14. The procedure came the day after Karlsson sustained the injury when he was stepped on by the Pittsburgh Penguins' Matt Cooke.

The timetable for Karlsson's recovery originally was estimated at six months, but Karlsson began skating about three weeks ago.

---End Update---

UPDATE: Thursday, Feb. 14, at 12:50 p.m ET by Timothy Rapp

Bad news, Senators fans—Karlsson is going to be out of commission for quite some time. From the team's official Twitter account:

"Erik had surgery this morning to repair a 70% cut in his achilles. Recovery time is 3-4 months" - #Sens GM Bryan Murray

— Ottawa Senators (@NHL_Sens) February 14, 2013

Karlsson's loss a devastating blow to OTT but also big loss for NHL/hockey. Karlsson has been best/most exciting NHL player so far this yr.

— Bob McKenzie (@TSNBobMcKenzie) February 14, 2013

Ottawa has made some calls to try and replace Karlsson in the lineup, but according to general manager Bryan Murray, there aren't any solid leads to follow up on.

"I've made some calls about different players. Nobody willing to give me a player for a player not in league yet." Says Murray. #Sens

— Bruce Garrioch (@SunGarrioch) February 14, 2013

Anaheim star Teemu Selanne had some very kind words to say about Karlsson to Elliotte Friedman of CBC.com.

Teemu Selanne on Erik Karlsson: "I want to wish Erik the best. It's a tough injury because it's bad luck. He can come back from this...

— Elliotte Friedman (@FriedgeHNIC) February 14, 2013

---End of update---

UPDATE: Thursday, Feb. 14, at 9:49 a.m ET by Brandon Galvin

Matt Cooke will not be disciplined by the NHL after his skate injured Erik Karlsson, according to Ottawa Sun's Bruce Garrioch.

Confirmed that Matt Cooke won't receive any discipline from the NHL department of safety. They saw no intent. Blast away fans. #Sens

— Bruce Garrioch (@SunGarrioch) February 14, 2013

---End of update---

UPDATE: Wednesday, Feb. 13, at 10:28 p.m. ET by Michael Moraitis

Here is what Matt Cooke had to say in regard to the play that injured Karlsson, per Josh Yohe of the Tribune-Review:

Dave Molinari of the Pittsburgh Post-Gazette gave us Cooke's response to early allegations that he injured Karlsson on purpose:

Senators general manager Bryan Murray will no doubt add fuel to the fire with this quote, per Josh Yohe of the Tribune-Review:

---End of Update---

Karlsson's injury happened on a play that's bound to create some controversy in the league office. As Matt Cooke checks him into the boards, you can noticeably see the Penguins left winger's skate land directly on Karlsson. 

You can judge Cooke's intent for yourself in the video, but TSN's Gord Miller is reporting that the Senators are (understandably) upset with the play. For his part, Cooke said that it was a "complete accident," according to Dave Molinari of the Pittsburgh Post-Gazette:

Cooke says Karlsson incident was "a complete accident."

— Dave Molinari (@MolinariPG) February 14, 2013

Regardless of what happened during the play in question, losing Karlsson is a critical blow for Ottawa. The 22-year-old Swede is seen as a cornerstone of the Senators franchise and has emerged as one of the NHL's brightest young stars.

Karlsson was awarded the James Norris Memorial Trophy in 2011-12 as the league's best defenseman and was the NHL's leading vote-getter for the All-Star Game last year. He finished the season with a whopping 78 points, cementing his reputation as arguably the best all-around defender in the league.

Though Ottawa is a middle-of-the-road 7-5-2 thus far, Karlsson has shown little sign of slowing down in this lockout-shortened campaign. He has 10 points in 14 games played through Wednesday night and was on his way to another stellar season.

With his status very much up in the air, it seems like the Senators will have to find production from somewhere else for the time being.

Be sure to check back in as we give you the latest updates on Karlsson's status and possible return date.