Jan 10 (Reuters) - Manchester United ( MANU ) forward Marcus Rashford is available for Sunday's FA Cup third-round tie at Arsenal after falling ill, manager Ruben Amorim said on Friday.

The 27-year-old Rashford was left out of the squad for four straight matches before being an unused substitute in United's home defeat to Newcastle United on Dec. 30. The academy product then fell ill and missed their 2-2 draw at Liverpool last week.

Amorim first dropped Rashford for the 2-1 derby win at Manchester City in mid-December, two days before the England international said he was "ready for a new challenge" after spending his entire career at United since the age of seven.

Rashford has scored 138 goals in 426 appearances since making his senior debut for the club in 2016, winning the Europa League, two FA Cups and the League Cup twice.

"Rashford and Kobbie Mainoo are available, they are training and we will see the selection for the game," the Portuguese coach told reporters on Friday.

Asked whether any academy players will be sold or loaned in the January transfer window, Amorim said: "Our idea is always to keep the best players and to build for this club, but I am really happy and I like our players.

"My players are always my favourites so I want to keep my players. It is a special moment in this club."

United won their 13th FA Cup last season and only Arsenal (14) have won the trophy more times. "We won some cups, we want to continue. We know at this stage we have a really tough match but we want to win," Amorim said.

United's number two goalkeeper, Altay Bayindir, who replaced Andre Onana in their League Cup quarter-final loss at Tottenham Hotspur last month, will start against the Gunners at the Emirates.

The 26-year-old Turkey international started all three of United's League Cup ties this season but faced criticism for errors in the 4-3 loss at Tottenham.

"I don't rotate (the squad) because I want to rotate," Amorim added.

"I'm trying to find the best solutions to win the game. I put the guys in who are more fresh to cope with the demands of the game. The goalkeeper position is different, Altay will play."