Solskjaer was asked about Mourinho's first interview since leaving United in which he suggested that player power forced him out of Old Trafford, and insisted that he would return to work at a top club.
"Alexis has trained all week so hopefully he'll be available and Felli is the long-term one that's out". He'll be out for a few weeks'. "He'll probably be at least three or four weeks [out] - he's got a calf problem and that's sad".
"It's not an easy task to come to Manchester United, taking over in such a very critical part of the season and he's been doing unbelievable", Rossi told PA Sport.
Fellaini has been a long-term target of Chinese clubs, with Shanghai SIPG and Guanghzou Evergrande previously making offers for the Belgium global.
The Seagulls have beaten the Reds on both their league visits to the Amex Stadium but United have seen them off twice at Old Trafford.
Arguably the most impressive victory in the sequence came last Sunday, when Tottenham were beaten 1-0 at Wembley thanks to a Marcus Rashford goal and an eye-catching goalkeeping display from David de Gea.
Mourinho also went on to say the reason he was working as a pundit was to "understand new football better" in possibly his most humble statement over the past 20 years.
"He's champing at the bit in training. He's attitude has been fantastic in training and I'm looking forward to seeing him".
A former super-sub himself, Solskjaer warned his players when he took over from Mourinho that some would have to take the opportunities given to them from the bench, and Belgium striker Lukaku has been one of the losers from the switch in tactics and positive vibes that have arrived under the Norwegian interim boss.