Is it permissible to buy things that are made from the skins of animals that were not slaughtered according to the shar‘i method?

The skins from which footballs or basketballs are made can
only be skins that have been tanned. Tanning means treating the skin with
things that clean it and purify it, to remove any smell, decay or
dampness. This is what usually happens. For the ruling on buying these
things, it is essential to know the kind of animal from the skin of which
it has been made; it can only be either an animal that it is permissible
to eat or an animal that it is not permissible to eat. 

(a)

If those things are made from the skin of an animal that may
be eaten — such as a cow — then tanning makes its skin permissible. If it
has been slaughtered according to shar‘i conditions, there is no need for
tanning. But if it was slaughtered by people who go against the laws of
Allah, may He be exalted, then it is maytah (dead meat), and the skin of an
animal that may be eaten but died without being properly slaughtered can
only become permissible by means of tanning. 

(b)

If these things are made from the skin of an animal that
cannot be eaten in the first place, such as a pig, then it is haraam to use
its skin even if it has been tanned. 

So with regard to animals whose meat may be eaten,
slaughtering them in accordance with sharee‘ah makes their meat and skin
permissible, and tanning makes their skin permissible if the animal died
without being slaughtered in accordance with sharee‘ah (maytah or “dead
meat”). 

In the case of animals that cannot be eaten, slaughtering
them in the shar‘i manner does not make their meat or skins permissible, and
tanning does not make their skins permissible. 

This is the view of al-Awza‘i, ‘Abd-Allah ibn al-Mubaarak,
Abu Thawr and Ishaaq ibn Raahawayh; it is one view narrated from Imam Ahmad;
and it is the view favoured by Shaykh al-Islam Ibn Taymiyah (may Allah have
mercy on him) according to one of his two opinions. 

See: Sharh Muslim by al-Nawawi, 4/54, where he (may
Allah have mercy on him) mentioned seven opinions on this matter;
al-Furoo‘ by Ibn Muflih 1/102; Majmoo‘ al-Fataawa by Ibn Taymiyah
21/95. 

This view was also favoured by a number of contemporary
scholars. 

Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allah have
mercy on him) said: 

And it was said that the skin of an animal that died without
being slaughtered correctly may be purified by means of tanning so long as
it comes from an animal that may be made permissible by means of proper
slaughter. But if it cannot be made permissible by means of proper
slaughter, then it cannot be purified. This view is most likely to be
correct. Based on that, the skin of a cat and any smaller animal cannot be
purified by means of tanning. 

The ruling is connected to whether the animal is regarded as
taahir (pure) when it is alive. If it is taahir (pure), then it is
permissible to use the skin of that animal if it died without being
slaughtered properly, after tanning it once it has dried. But according to
the madhhab it cannot be purified. According to the second opinion, it can
be purified, and according to the third opinion, it becomes pure through
tanning if it is from a dead animal that would be permissible (to eat) if
slaughtered properly. 

The most correct view is the third one, based on the fact
that in some versions of the hadeeth it says: “Its tanning is its
purification” (narrated by al-Nasaa’i, 4243; classed as saheeh by al-Haafiz
ibn Hajar in al-Talkhees al-Habeer, 1/49). So the word purification
was used, and it is well known that slaughter does not purify anything
except that which it is permissible to eat. If you slaughtered a donkey and
mentioned the name of Allah over it and shed its blood, it still could not
be called halaal slaughter. 

Based on this we say: the skin of an animal that it is haraam
to eat, even if it is regarded as taahir when alive, cannot be purified by
tanning. 

The reason for that is that the animal that is taahir when it
is alive was regarded as taahir because it is too difficult to avoid them
completely, because the Prophet (blessings and peace of Allah be upon him)
said: “They are among those who go around among you” — referring to cats.
This hadeeth was narrated by al-Tirmidhi (92), Abu Dawood (75), al-Nasaa’i
(68) and Ibn Maajah (368), and was classed as saheeh by al-Bukhaari,
al-Tirmidhi, al-Daaraqutni and al-‘Aqeeli, as stated by Ibn Hajar in
al-Talkhees al-Habeer (1/41). This reason ceases to apply when the
animal dies, whereupon it goes back to its original state, which is najaasah
(impurity), and it cannot be purified by means of tanning. 

So the correct view is that any animal that dies and may be
eaten, its skin is purified by tanning. This is one of the two opinions of
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him); he has another
opinion which is in accordance with the view of those who say that whatever
was taahir when it was alive, its skin may be purified by tanning. 

Al-Sharh al-Mumti‘, 1/74, 75 

To sum up: 

It is permissible for you to buy a football or basketball
that is made from the skin of an animal whose meat may be eaten. Whatever
was slaughtered in a way other than the shar‘i way or died of natural causes
without being slaughtered at all, tanning its skin makes it taahir (pure)
because of the hadeeth of Zayd ibn Thaabit (may Allah be pleased with him),
from the Prophet (blessings and peace of Allah be upon him) who said:
“Tanning the skin of the dead animal (that died without being slaughtered)
is its purification.”

Narrated by Ibn Hibbaan (1290) and al-Daaraqutni (25);
classed as saheeh by al-Albaani. 

See also the answers to questions no.
9022 and
1695. 

And Allah knows best.