Rashford missed England's European Championship qualifying wins over Italy and Ukraine after withdrawing from the squad earlier this month due to a knock he suffered during United's FA Cup quarter-final win over Fulham.
Rashford is United's top scorer this season and has been in scintillating form with 30 goals for club and country.
"I have good hope, he trained but he had to do some treatment, he had to do some individual training. Today he joined in with the group," Ten Hag told reporters ahead of Sunday's trip to Newcastle United.
"We have one more day, so I have a good hope he will be available... I have seen him back this week and he has shown a lot of energy, a lot of motivation. It was a good spirit and a lot of focus."
Rashford's rise this season has seen him linked with a move to top European sides but Ten Hag said he wants to keep the club's talisman with talks ongoing over a contract extension. Rashford's current deal ends next season.
"It's an internal process. We focus on winning games, of course also planning for the future, so in the back we're working on that," Ten Hag added.
"It's about agents, it's about football director John Murtough. Rashy and I are focusing on performing."
Ten Hag also said injured French forward Anthony Martial could make his return for the first time in two months.
United are third in the Premier League with 50 points but fifth-placed Newcastle can overhaul Ten Hag's side on goal difference if they win at St James' Park.
Newcastle have the best defensive record in the league this season having conceded only 19 goals in 26 games but the Dutch boss was more concerned about their time-wasting tactics.
"We know they delay, it's something that the refereeing doesn't want. They want to have tempo in the game, that is the aim of the Premier League, so they have to be consistent to let the game go," Ten Hag said.
"They've had a great season with their manager (Eddie Howe)... It's a team that is really hard to beat. We are looking forward to the challenge and the evidence is we can beat them."
