Muhammad engaged in a number of battles in his lifetime; see Wikipedia for a list. If it were anyone else, it stands to reason that he could have been killed in any of these. Of course, Muhammad had an essential task to accomplish, conveying the Qur'an, and being killed would have left it incomplete. So perhaps Allah would not have allowed this to happen.
Question: Could Muhammad have been killed in battle?
I'm seeking scholarly opinion on this matter, i.e., what's generally agreed upon, and not simply some Internet theory. So please back up any answers.
What I know so far:
Qur'an 2:61 says "...that was because they [repeatedly] disbelieved in the signs of Allah and killed the prophets without right...". So it seems it is possible to kill prophets without Allah's intervention.
Muhammad did eventually die. As I understand, he was eventually killed by being poisoned:
A Jewess brought a poisoned (cooked) sheep for the Prophet who ate from it. She was brought to the Prophet and he was asked, "Shall we kill her?" He said, "No." I continued to see the effect of the poison on the palate of the mouth of Allah's Messenger. -- Narrated Anas bin Malik (sunnah.com)
Googling the title of this question yields a bunch of unflattering and unhelpful webpages. Actually, I'm not sure where to look in answering this question.
(And apologies for asking about this unpleasant topic.)