On the one hand, already having a DCEU appearance on his resume might hurt Common’s chances of playing John Stewart.
On the other hand, Monster T was so minor a character that DC could easily get away with bringing Common back in a different capacity if they wanted to.
Take away the tattoos and piercings, put him in a green and black uniform, problem solved.
As we mentioned earlier, Common has already left his mark on the DCEU in Suicide Squad, where he played a criminal named Monster T. However, the appearance basically amounted to a cameo, as he was swiftly killed by The Joker after making an inappropriate comment about Harley Quinn.