Marshall yesterday revealed that he was frustrated by a hip injury that is threatening his place in the starting lineup for the Bears' opening match of the regular season.
The 29-year-old also missed training today, although both he and coach Marc Trestman have confirmed that his absence had always been planned, and agent Kennard McGuire believes that to think differently is unfair on his client.
"Brandon is accustomed to executing and playing at a high level, and being the perfectionist that he is, his expectations of himself are very high. Anything less than elite is unacceptable to him," McGuire is quoted as saying by ESPN.
"As far as him not being there, this has been planned with the Bears and Brandon long before yesterday. Any other suggestion, thought or implication are all unfair to Brandon and the Bears organization."
The Bears are still hopeful that Marshall will be able to fully recover in time for their regular season opener against the Cincinnati Bengals on September 8.