Ryan, 31, who has six goals and 18 points in 29 games, has missed three games with a concussion.
"It's a concussion thing, so the minute he's cleared (he'll play), and he's doing really good," Senators coach Guy Boucher told the Ottawa Sun after the team arrived in Detroit on Wednesday. "So if his baseline is clear, then that's a clear one and, hopefully, we get good news from that.
"Of course, that's what I'm hoping. But what I'm hoping and what's reality is often not the same. From what I hear, things are going good, I just have to wait to see now if they have taken the last step."
"Whenever you get guys like that back, it also gives the young guys a bit more breathing room because they don't feel the pressure is on them," Boucher said. "It's a fine line between giving them ice and responsibilities. Sometimes they have too much.
"You've got to navigate it, but it's hard to do when you've got that many guys injured; it's actually impossible to do when you have that many guys injured, and that's where we're at. When you get guys back who can sustain what you're doing, it's hard for the opponent and it's easier for you. It's a double effect."
The Red Wings (14-14-4) have been struggling on the power play. They have converted only 2-of-31 power plays in their past 14 games, which is a big dip from their first 18 games (13-of-54).
"The one hard thing about our power play is we don't get very many of them, so then it's hard to get any kind of rhythm," Detroit coach Jeff Blashill told www.mlive.com.
He tried using centers Dylan Larkin and Frans Nielsen on the same unit in Tuesday night's 6-2 road loss to the Washington Capitals.
"Moving Larks (Larkin) into that bumper spot and moving (Andreas Athanasiou) to the half-wall spot, where it's more run through him as opposed to running the other side and being a one-timer, we're hoping to get some chemistry going." Blashill said.
The Red Wings have had only one power play in each of their past two games and 85 for the season. They had 106 through 32 games in 2017-18.
"We've been in a lot of games where there hasn't been a whole lot called," Blashill said. "Since the beginning of the year, when we were leading the league in power plays given up, we've been in lots of games after that where there hasn't been much called either way. Do I sense it's relaxing? I don't know. I think every game takes a life of its own. I can't say sit there and say a bunch of games they've missed lots of calls on either side. They generally do a real good job. Maybe it's just the way the game has been."
Defensemen Mike Green and Jonathan Ericsson didn't practice Thursday. Blashill said they are both banged up and questionable for Friday night. Detroit is carrying two extra defensemen, Luke Witkowski and Brian Lashoff.