Jetro Willems, Paul Dummett, Dwight Gayle and Ciaran Clark all took part in the first session of the week on Monday after overcoming injuries, while Miguel Almirón and Andy Carroll resumed training on Tuesday.
Willems suffered a groin injury against Leicester City on New Year's Day while Dummett has missed the last four matches, also with a groin injury.
Gayle had a slight hamstring problem while Clark sustained a calf injury in last month's home win against Southampton. Almirón came off against Rochdale at the weekend and Carroll missed the game with a minor hamstring complaint, but all six could now come into contention for Saturday's Premier League trip to Wolverhampton Wanderers.
Captain Jamaal Lascelles, who hasn't played since he was hurt in November's victory over AFC Bournemouth, will also be back in full training later this week.
On Saturday, Matt Ritchie made his first appearance since he was injured by a Hamza Choudhury tackle in August's Carabao Cup tie against Leicester. He came on as a 64th-minute substitute at the Crown Oil Arena.
Meanwhile Allan Saint-Maximin has also been back on the grass over the last few days as he makes good progress in his recovery from a hamstring injury.