Bailly and Maguire were paired together for the 3-0 Carabao Cup win over Luton in midweek after usual first-choice Victor Lindelof put in a disastrous performance during the defeat to Crystal Palace in United's opening Premier League game of the season.
Bailly is fit again after being restricted to just 11 appearances in all competitions last season and ahead of the trip to Brighton on Saturday, Solskjaer was keen to talk him up.
"Last week wasn't fantastic [against Crystal Palace], we conceded sloppy goals," Solskjaer told a news conference on Friday.
"Eric is fit again -- a big, big plus -- and we're looking forward to seeing him develop and play more games. We've been waiting for him to be fit and play more regularly."
Solskjaer also has Chris Smalling available in defence but hinted the 30-year-old won't be considered for selection while talks about a return to Roma are ongoing.
"Different things need to happen [for Smalling to play]," Solskjaer said.
"So let's wait and see if there's that change. Let's see what happens when the transfer window closes and what happens to Chris."
With just over a week to go before the transfer window closes, United are still in the hunt for new players while a number of the bloated first-team squad could be allowed to leave.
Sources have told ESPN that United are still hopeful a deal for Jadon Sancho could be reached with Borussia Dortmund before the deadline on Oct. 5 while there remains interest in Porto left-back Alex Telles.
"As I've said so many times, I'm very confident in my players and if and when something happens with ins and outs we'll update you," Solskjaer said.
"In football you can't predict too much but for me we're just working on getting better, my focus is solely on the game. We can't be thinking any other way."