Ericsson said he wasn't getting more than 10 minutes of sleep at a time because he couldn't lie down.
The Red Wings haven't yet set a target date for him to return to action.
"That was my first practice with the guys," Ericsson said. "I skated by myself here for a couple of days. I'll just take it day by day and see how it feels, try to get more movement every day."
Unfortunately, when Ericsson does come back, he'll have to wear the full cage for a period of time, something he hasn't done since he was 17 years old.
"I think, I don't want to say how long but I think it's going to be a while," Ericsson said. "I didn't think it was going to be that big of a difference. Obviously I've played without anything. I think just a shield is terrible. Going to a cage is even worse. Yeah, it's not fun."
The only silver lining in the situation was Ericsson was able to remain home during the holidays, even if he didn't feel quite up to snuff.
"I wasn't very up and running and playful as maybe normal, but it was nice to be home," he said.
ATHANASIOU'S SEASON: It has been a strange season for several Red Wings, including Andreas Athanasiou.
Athanasiou had a breakout year last season with career highs in goals with 30 and assists with 24 in 76 games.
This season, Athanasiou was hindered by a couple of injuries in training camp and the preseason, causing him to miss the first two regular-season games.
He also missed two games against Winnipeg, Dec. 10 in Winnipeg and Dec. 12 in Detroit.
Through his first 36 games of this season, Athanasiou has five goals, 14 assists and is minus-35.
Through his first 36 games last season, Athanasiou had 14 goals, 10 assists and was even.
"I think the beginning of the year, he was getting chances but it wasn't quite to the level it was that it was probably at the start of last year," Wings coach Jeff Blashill said. "He missed a lot of time in training camp with the injury. It's hard to miss time and get going at full speed. I think he's done a good job of choosing to make the right decisions from here in the last bit."