Each of the 11 players on a team is assigned to a particular position on the field. There are 17 FIFA 21 positions available in FUT. They describe both the player’s main role and their area of operation on the pitch.
FIFA 21 Positions
Description of all FIFA 21 positions you can find on Ultimate Team game mode.
Goalkeeper is the most defensive position in football. Their job is mainly defensive: to guard the team’s goal from being breached (to not let the other team score). Goalkeepers are the only players allowed to touch the ball with their hands and arms, however, they are restricted to doing so only within 18-yard box; for this reason, they must wear jerseys that distinguish them from other outfield players and the referee.

Right-Backs and Left-Backs are the defenders stationed either side of the centre-backs to provide protection from attacking wide players. They often have to defend against the opponent’s wingers, who will try to take the ball past them down the flanks in order to cross or pass into the penalty area to their attackers. They also take thrown-ins and provide support for the wide midfield ahead of them, eventually overlapping and sendings crosses into the opposition box.

Right Wing-Backs and Left Wing-Backs are a modern variation of full-backs. Basically, they are defenders with a heavier emphasis on attack. They are expected to stay on their touchline, overlaps and sends crosses into the opposition box but still marks opposition wingers when needed. It is one of the most physically demanding positions in modern football.

Centre-backs play in a central position of the defence. Their job is to stop opposing players, particularly the strikers, from scoring and bring the ball out from their penalty area. CBs are often tall, strong and have a good jumping, heading and tackling ability. Successful centre-backs also need to be able to concentrate, read the game well and be brave and decisive in making last-ditch tackles on attacking players who might otherwise be through on goal.

Defensive midfielders are stationed in front of the defenders to provide a more secure defence, thus “holding back” the freedom of the opponents to attack. The CDM screens the defence by harrying and tackling the opposition teams’ attackers and defenders. They also help tactically, for instance, by directing central attacking players out to the wing where they have more limited influence and by covering the positions of full-backs, midfielders and even the centre-backs as they charge up into the attack.

Central midfielders play several roles on the field of play, depending on their particular strengths and the tactics of the team. They are the link between defence and attack, and must also defend when the opposition is in possession. Their central position enables them to have an all-round view of the match, and as most of the action takes place in and around their area of the pitch, midfielders often exert the greatest degree of control over how a match is played.

Attacking midfielders are positioned in an advanced midfield position, usually between central midfield and the team’s forwards. Their main role is to create goal-scoring opportunities using superior vision and skill. The attacking midfielder is an important position that requires the player to possess superior technical abilities in terms of passing and, perhaps more importantly, the ability to read the opposing defence in order to deliver defence-splitting passes to the strikers.

Right and Left Midfielders are stationed in a wide position effectively hugging the touchline. Like all attacking players, wide midfielders need to have ‘off-the-ball’ intelligence, by being able to read passes from the midfield that give them a clear crossing or scoring opportunity. Usually, right-footed players are played on the right flank and left-footed players on the left as a matter of familiarity and comfort.

Right and Left Wingers are stationed in a wide position near the touchlines. A winger’s main attribute is usually speed, which is used to attack and dribble past opponent’s full-backs in order to get behind the defence and to then deliver crosses and passes into the centre for their attackers. Occasionally they may swap sides of the field as a tactical move.

Right and Left Forwards play along the wing. This position is similar to a winger but a wide forward plays on the front line and emphasizes more on beating defenders than crossing the ball. Wingers and wide forwards share many similarities such as needing crossing, dribbling and pace. This is the rarest position in FUT (only shows up on the 3421 formation).

Centre-forwards are positioned between midfield and attack. They have two roles: first, they score goals through passes from teammates; second, they distract the defence to give room for the attacking midfielder, winger or withdrawn striker to attack. They usually need a good vision, technical and creative skills.

Strikers are positioned nearest to the opposing team’s goal. Their primary responsibility is to score goals and to create scoring chances for other players. They can also hold the ball up until teammates can join the attack and harry opposition defenders and goalkeepers whilst not in possession. A striker must be brilliant at receiving and controlling the ball, strong and capable of winning the ball in the air.
FIFA 21 Positions abbreviations in different languages.
Players are used to play on a determined position but they can adapt themselves to similar FIFA 21 positions.

According to his positioning, a player may be in one of the following situations:
Playing in his natural position;
Playing in a position that is very similar to his natural position;
Playing in a position that has some similarities to the natural position;
Playing in a position that is very different from the natural position.

The position health is found directly underneath the player card: green means that he is playing on his natural position, orange means that he is playing in an adapted position and red means that he is playing on a position that is very different from the natural position.

When a player’s preferred position doesn’t match with the position he’s about to play, his chemistry is affected but it’s possible to fix this using a position modifier item.

FIFA 21 Positions and how chemistry is affected
FIFA 21 Positions - Modifier Items

Position Modifier Items are responsible to modify the position of a player.

Although players could play in any position, the team’s chemistry and the individual chemistry are strengthened if they are placed in their favourite positions or, at least, in similar positions. As it is not always possible to make these positions match, there are modifier items that help you to solve this problem.

Position Modifier items allow you to change the preferred position of a player to the one that is printed on his item. For each item that you use, you can change a single player’s position once. Using several items, you can change the player’s position as many times as you want, including getting back to his original position. Before applying one of these items, make sure that the player already doesn’t have maximum individual chemistry. If he does, you don’t have to use the modifier item. Keep in mind that the modifier items contain information about the old and the new position. If a player’s favourite position doesn’t match with the old position printed on the item, you cannot apply that item to him.

Each position item can only be applied to a player and the effect lasts until you use a new position item on him. Sometimes, you need to use several items to get the position you want. For example: to transform a CAM into an ST, you need to use a CAM-CF item and then a CF-ST item. In other hand, goalkeepers’ position cannot be changed to anything else.