Looking on the internet deeply has found these results:

They are playing football in the field is the most popular phrase on the web.

They are playing football on the field 10 results on the web	They are playing football in the field 13 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	... is correct?1. They are playing football at the field.2. They are playing football in the field.Thanks. asked Mar 28 '12 at 09:34 May New member � link comment�... 4. He is making a cake now. 5. she is sewing a shirt now. Communicative English Course 1 16 Tenses In English 6. They are playing football in the field now. 7. 22 ?.?. 2014 ... i1'ltJll1~fll~W'Vllfl~9ffltJ'tJ'U1Jlflfl "L1'ilflfl1Jl()~" 'il::f1~ 0 l'U1tJ'tJfJ~ Present Simple Tense ~ they are playing football in the field, a dog runs in.

They are playing football on the field

10 results on the web

They are playing football in the field

13 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

... is correct?1. They are playing football at the field.2. They are playing football in the field.Thanks. asked Mar 28 '12 at 09:34 May New member � link comment�...
4. He is making a cake now. 5. she is sewing a shirt now. Communicative English Course 1 16 Tenses In English 6. They are playing football in the field now. 7.
22 ?.?. 2014 ... i1'ltJll1~fll~W'Vllfl~9ffltJ'tJ'U1Jlflfl "L1'ilflfl1Jl()~" 'il::f1~ 0 l'U1tJ'tJfJ~ Present Simple Tense ~ they are playing football in the field, a dog runs in.