A thirst for fighting in the octagon might be too much for 40-year-old Brock Lesnar to stay away from.
According to Wrestling Observer, the retired former UFC heavyweight champion "is quietly back in the USADA testing pool for UFC, meaning that rumors about him potentially returning to fight have some substance."
Lesnar's last fight was in August of 2016 when he defeated Mark Hunt in a unanimous decision. The victory was overturned months later after two pre-fight drug tests came back positive for a form of an estrogen blocker, ultimately resulting in a one-year suspension for Lesnar.
That suspension went into a holding period when Lesnar reportedly informed the UFC of retirement, MMAFighting.com reports, meaning if he were to un-retire he would need to serve out the remaining five months of his ban.
If the report that he's back in the testing pool is true, it's a pretty clear-cut sign that he's considering a comeback.
Additionally, there's internet buzz that Lesnar plans to drop his WWE Universal Championship at Summerslam in August, thus paving the way for a UFC comeback.