Question: Are our children allowed to play football in the back garden on Shabbos?
Answer: The Beis Yosef (OC 308) quotes opposing views as to whether one may play with a ball on Shabbos. The Shibolei Haleket (121) prohibits it as balls have no constructive use and are dirty. Tosafos (Beitza 12a), however, permits playing. Following this, he writes (Shulchan Aruch OC 308:45) that one mustn’t play with a ball on Shabbos or Yom Tov. The Rema, however, writes that the custom is to be lenient on this matter. The Rema adds (OC 518:1) that on Yom Tov one may even play with a ball in a reshus harabim.
Thus, the Shulchan Aruch Harav (OC 308:83) and Aruch Hashulchan (OC 308:70; 518:8) write that it is commonly accepted that one may play with balls on Shabbos.
Nonetheless, the Taz (OC 518:2) and Magen Avraham (OC 518:4) write that while children can play, this is inappropriate for adults (See Shemiras Shabbos Kehilchasa 16:1; 6).
Likewise, the Mishna Berura (308:158; 518:9) writes that balls aren’t muktze as they are made for playing with. While playing outside is problematic because one may come to smooth the ground (ashvei gumos, See Shulchan Aruch OC 338:5), one doesn’t need to stop children playing. R’ Shmuel Wosner (Shevet Halevi 9:78), writes, too, that one may play with balls indoors.
R’ Ben Tzion Abba Shaul, Ohr Letzion (2:26:8) writes that while sefardim would follow the Shulchan Aruch who doesn’t allow playing with balls, one can rely on the Rema’s lenient position for children.In conclusion, while balls aren’t muktze, adults should ideally not play with them on Shabbos. Ideally, children also shouldn’t play football on grass or soil, though one doesn’t need to stop them from playing.