Una lesión leve obligó a una defensa a salir del campo.

Yes, it can be a bit of a false friend. In Spanish, lesión very commonly means injury, especially in medical or sports contexts.

So una lesión leve means a minor/slight injury.

In English, lesion sounds more medical and narrower, but in Spanish lesión is a normal everyday word for an injury.

In Spanish, adjectives often come after the noun.

So:

• una lesión leve = a minor injury

This is the most neutral, standard order. Putting leve before the noun would sound unusual here.

Here, defensa means defender, as in a sports player, especially in football/soccer.

So:

• una defensa = a female defender

In other contexts, defensa can also mean:

• defence
• protection
• defense in the legal or argumentative sense

But salir del campo makes the sports meaning clear here.

Defensa is often used as a common-gender noun for the playing position.

So:

• un defensa = a male defender
• una defensa = a female defender

You may also see defensora, but in sports reporting defensa is very common for the position itself.

Obligó is the preterite (simple past), third person singular, of obligar.

So it means:

• he/she/it forced
• made someone do something

Here the subject is una lesión leve, so literally:

• A minor injury forced...

The accent matters:

• obligo = I force / I am forcing (present, without accent)
• obligó = he/she/it forced (preterite, with accent)

They do two different jobs.

1. The first a is the personal a, used before a person:

   • obligó a una defensa = forced a defender

2. The second a is part of the structure:

   • obligar a alguien a + infinitive
   • to force someone to do something

So:

• obligó a una defensa a salir = forced a defender to leave

It is the direct object, even though it has a.

That a is the personal a, which Spanish uses before specific human beings.

So in:

• Una lesión leve obligó a una defensa a salir del campo

the roles are:

• Una lesión leve = subject
• a una defensa = direct object
• a salir del campo = what the defender was forced to do

Because de + el contracts to del.

So:

• de el campo → del campo

This is a standard contraction in Spanish.

Similarly:

• a + el → al

Literally, it means to leave the field.

In sports, a more natural English translation is often:

• to leave the pitch
• to go off the field
• to be taken off

In Spain, campo is very common in football/soccer language.

Grammatically, the sentence says that the injury caused the defender to leave the field.

Structure:

• Una lesión leve = the cause
• obligó = forced
• a una defensa = the person affected
• a salir del campo = the action she had to do

In sports writing, this is a very normal way to say that a player had to go off because of an injury.

Yes. Leve often means:

• mild
• slight
• minor

Which English word sounds best depends on context:

• una lesión leve = a minor injury
• síntomas leves = mild symptoms
• un golpe leve = a slight blow

Here, minor injury is probably the most natural translation.