Manchester United quartet Phil Jones, Chris Smalling, Paul Pogba and Eric Bailly have trained ahead of their Europa League semi-final first-leg tie at Celta Vigo on Thursday.
England defenders Jones and Smalling were at United's Carrington training ground on Wednesday, along with Pogba and Bailly.
Jones injured his foot in a training ground challenge with fellow centre-back Smalling ahead of England's 1-0 friendly defeat to Germany in March, while Smalling himself was forced off in that game with a knee problem.
Neither player has featured since the 3-1 Premier League victory at Middlesbrough on March 19.
That had left Mourinho with selection concerns in defence ahead of their opening game against Celta Vigo in Spain.
But that has eased somewhat with the England duo now back in training while Bailly, who twisted his ankle in Sunday's 1-1 draw with Swansea, could also now feature.
Mourinho had previously indicated that Matteo Darmian, Michael Carrick or youngster Axel Tuanzebe may therefore have to be drafted into the central defence.
Pogba was also spotted at United's training ground as he battles back from a hamstring injury to offer his manager a welcome boost ahead of their latest European adventure.