The 20-year-old, Frodsham-born centre-back, who turned professional in the summer of 2016, has struggled to secure first-team football since signing his first pro-deal and is currently a free agent after leaving the Racecourse Ground at the end of last season.
Despite Marx appearing in the Saddlers team to play Rushall Olympic this evening, Walsall are yet to confirm who is on trial with the club but are understood to be looking to add a few players ahead of Deadline Day with the gaffer keen to have a settled squad before they begin their attempt to improve upon last season's relegation-battling campaign.