In and out of the lineup since spraining the medial-collateral ligament and patella (kneecap) in his left knee during practice Nov. 23, Staios aggravated the injury March 7 against Tampa Bay. He hasn't played since.
Staios will miss the team's final nine games, leaving the Oilers' injury-riddled defence short his 677 games of NHL experience and with four rookies in the lineup. No date for surgery is set.
"I feel comfortable with the decision," Staios said. "We've taken some time to think about it and do the right thing.
"It's something that, as a player, you go out there and you realize you aren't right, but you want to be in there. It was frustrating for me."
Staios, 33, had a streak of 224 consecutive games played ended by the injury when he sat out against the Chicago Blackhawks on Nov. 24.
Staios had missed a total of 15 games, including Edmonton's last six outings, before the decision was made to have the surgery. Recovery is expected to take four months.
"There's the option of doing rehab (rather than surgery) and then coming back and seeing how it is," Staios said. "I want to take all that sort of risk out of the way. That's why I'm going ahead with the decision."
With Staios set for surgery and Daniel Tjarnqvist having had a sports hernia repaired this week, the blue-line is being manned by captain Jason Smith, second-year rearguard Matt Greene and rookies Ladislav Smid, Bryan Young and Dan Syvret. Junior call-up Sebastien Bisaillon is also in the mix.
"He's been battling this awhile," coach Craig MacTavish said of Staios. "We have to get it fixed so we can properly evaluate him. How much was it impacting his game?
"He was, clearly, not the same player for at least the last few weeks playing through the injury. Hopefully, this is the thing that will get it sorted out."
After Smith, who has 859 NHL games on his resume, Staios is the team's most experienced defenceman. Tjarnqvist has 315 games.
Greene, Smid, Young, Syvret and Bisaillon, who made his debut in Monday's 2-1 loss to the Vancouver Canucks, have played a combined 191 games.
"It's one of those things where it's a little bit pain, but mostly you just feel it sliding and you don't have the stability," Staios said. "That was a very, very frustrating thing for me.
"I got off to a good start and was really looking to put together a solid season for the team."
Staios, injured two days after signing a four-year contract extension worth $10.8 million Nov. 21, says he expects to be healthy in time for training camp.
"The timing is right," Staios said. "The sooner the better. Four months sounds like a long time, but I think I'll be on the ice before that."
Notes: Rookie defenceman Tom Gilbert, out for 12 games with a concussion, skated Tuesday and could be ready to return to when the team opens a six-game road trip in Nashville. . . . Rookie Mathieu Roy remains out with a concussion, as does forward Jarret Stoll.