MANCHESTER -- Marcus Rashford will be assessed this week after the Manchester United forward suffered a muscle injury during the win over Huddersfield on Saturday, sources have told ESPN FC.

Rashford, 20, came on as a 71st-minute substitute in the 2-0 victory at Old Trafford but felt a strain at the top of his left leg during his 20-minute appearance.

He is set to be monitored by United medical staff this week before a decision is made on whether he is fit to travel to Newcastle on Sunday.

Sources have told ESPN FC that there is hope Rashford will be passed fit for the clash at St James' Park after he was able to finish the game against Huddersfield.

The forward has been in Jose Mourinho's matchday squad for each of United's 38 games so far this season and has failed to feature in only one -- the 2-0 defeat at Tottenham last week.

United are again expected to be without Eric Bailly and Zlatan Ibrahimovic against Newcastle as they continue their recoveries from ankle and knee injuries respectively.

Marouane Fellaini has been ruled out for two months after undergoing knee surgery on Saturday, while Daley Blind is nearing a comeback after missing the last five games with an ankle ligament problem.

United head into the weekend 13 points behind Premier League leaders Manchester City, and Mourinho had suggested last week that the title race was over.

But after City drew at Burnley on Saturday and United followed up with three points against Huddersfield, defender Antonio Valencia said he was not giving up.

He said: "We need to keep fighting until the end, we need to keep going.

"Years ago we lost a title that we were eight points ahead and there were only six games left, now we have a lot more games to play and we need to keep fighting."

United's challenge has been bolstered by the arrival of Alexis Sanchez, who scored on his home debut against Huddersfield.

Valencia added: "We knew Alexis, he has now years playing at the highest level in the Premier League, and that is why he is here.

"He showed he is a great player and we hope he continues like this.

"Of course because of the way Alexis plays, always wanting the ball, he always wants to show what he can do and that is important for us."