Step 1: The number of ways to choose 11 players from 15 is given by the combination formula:
\[ {}^{15}C_{11} = {}^{15}C_{4} \]
Step 2: Calculate \( {}^{15}C_{4} \):
\[ {}^{15}C_{4} = \frac{15 \times 14 \times 13 \times 12}{4 \times 3 \times 2 \times 1} \]
\[ = 1365 \]