Definition: In this task, you need to reverse all words of a given length in the sentence. The number of letters in a word determine its length. For example, the length of the word "apple" is 5.
Input: Sentence: 'a baseball player holds his bat off to the side as he approaches the plate'. Reverse all words of length '4' in the given sentence.

a baseball player holds his bat off to the edis as he approaches the plate