Wallace is a restricted free agent (RFA), still tied to the L.A. Clippers. The linked article is an extremely lengthy, detailed discussion of a) the difference between RFA and unrestricted FA - i.e., the rules governing who is eligible for each; b) Montrezl Harrell's situation; c) Tyrone's situation. I.e., if you are roughly familiar with NBA restricted free agency and want to focus on Tyrone's prospects and options, skip down near the bottom to the paragraph beginning with: "Tyrone Wallace, on the other hand, is in an even worse situation than Montrezl."

https://www.clipsnation.com/2018/7/5/17535892/nba-off-season-2018-a-look-at-the-clippers-restricted-free-agents-montrezl-harrell-tyrone-wallace

It is possible that Wallace could be signed again to a 2-way G-league contract with the LAC for the 2018-19 season. He really needs another NBA team to offer him at least the veteran's minimum to assure a spot on an NBA roster. He doesn't have much leverage with the Clippers unless another team forces their hand.