21-year-old, Liverpool-born Brewitt is a product of his hometown club's academy system, where he rose through the various age groups before leaving the Merseyside club in favour of a switch to Middlesbrough last summer.
Brewitt, who captained Boro's Under-23s last season, is believed to have line up alongside Jon Guthrie as the Saddlers faced Aston Villa on Tuesday evening and entered a fairly good display as Dean Keates' side were defeated by four-goals-to-one in front of just over 3,500 supporters at Banks's Stadium.
The central defender, who represented England at under-16 and under-17s, is yet to make his professional debut so wouldn't add much in the way of experience to the Saddlers' poorly stocked backline but is believed to have several suitors and ranks among the many players yet to get a real opportunity to prove their worth.
Tom is a free agent after electing to go in search of first-team football at the end of last season as it is understood that he and Middlesbrough came to an agreement to allow him to depart the North East and seek employment elsewhere.
Walsall are yet to comment about any of their current trialists and are not expected to release any information until a contract is agreed between the two parties.