why does this query not use a parallel query

Have a query:

explain analyze SELECT minion_id FROM mob_player_mob_118 WHERE player_id =
55351078;

QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
Index Only Scan using mob_player_mob_118_pkey on mob_player_mob_118
(cost=0.44..117887.06 rows=4623076 width=4) (actual time=0.062..3716.105
rows=4625123 loops=1)
Index Cond: (player_id = 55351078)
Heap Fetches: 1152408
Planning time: 0.241 ms
Execution time: 5272.171 ms

If I just get the count it will use a parallel query

explain analyze SELECT count(minion_id) FROM mob_player_mob_118 WHERE
player_id = 55351078;

Thanks

Dave Cramer