Chilean forward Sanchez, who scored 47 times in 141 appearances with Barca between 2011 and 2014, has not featured since picking up a knee injury against Southampton last month, while Matic is recovering from a muscle injury.
United lost the home leg against Paris St Germain in the previous round 2-0 before turning the tie around in the French capital, and Solskjaer is hopeful his players can serve up a repeat at the Nou Camp.
"I think I'll be so focused, so concentrated," Solskjaer told the BBC.
"I'll have my last little gut feeling on who to play.
"Because against PSG I had a team in my mind when we travelled in the morning, walk out into the stadium, see the stadium and you say 'nah, I'll change, I need to do this, he needs to play' and it turned out ok."
The Nou Camp has an added significance for Solskjaer after he scored a stoppage-time winner in the 1999 Champions League final against Bayern Munich at the stadium in United's treble-winning season.
"That goal has been mentioned a few times, yes," the 46-year-old said.
"So many people have congratulated me and talked to me about that night. They say 'it was the best night of my life but don't tell my wife' -- that kind of thing."
United's short-term target is to secure a Premier League top-four finish and qualification for the Champions League, but Solskjaer wants the club to compete for major honours next season.
He stressed it was important to have strong characters in the dressing room if United are to compete with Europe's elite on a regular basis.
"If you want to win, if you want to play at Man United you have to have a personality," Solskjaer added.
"You have to stand up for yourself against big boys because you're going to play against top players in the world and then you can't look round and always ask for help. We all have to step up."
(Reporting by Hardik Vyas in Bengaluru; Editing by Toby Davis)
