The phrase "in left field" is commonly used to describe something that is unexpected or unusual. Synonyms for this phrase may include "out of the blue," "offbeat," "unconventional," "odd," "quirky," and "off the wall." Other synonyms may include "peculiar," "weird," "eccentric," "abnormal," "unique," and "strange." These words can be used in a variety of contexts, such as in describing a person's behavior or a situation that is out of the ordinary. Regardless of the situation, there are many words that can be used to replace "in left field" and convey the same sense of unexpectedness or peculiarity.