Our football team had two injured players; we lost the game.
Explanation:
One of the most common uses of semicolon is to join two independent clauses without having to appeal to a conjunction (such as "and"). In this case, we have <em>"Our football team had two injured players"</em> and <em>"We lost the game"</em>. Both of them are independent clauses, therefore the use of semicolon is correct in this sentence.
