Brian Cushing said Thursday that he neither injected nor ingested any banned substances, even though he tested positive for a performance-enhancing drug. Cushing was suspended for four games without pay last week for violating the NFL's drug policy. His appeal was denied. Cushing confirmed that he tested positive for HCG, a fertility drug that's on the league's banned substance list. "The question of how it got into my body is still unclear," he said. "It's something that I'm very personally concerned about, just the fact that how it's there and what's going to determine it from happening again, and that's something we're going to have to medically investigate." Cushing said that after failing the test, he was told HCG can get in your body from injecting it or because of tumors. He said this information led him to believe he had tumors, although he didn't say what kind. "I personally know I'm not injecting myself with anything," he said. "I played the whole season thinking this could not only be my last season, but my last year." Cushing added that he's concerned about his health and plans to undergo tests to see "how this got into my body" and to try to make sure it doesn't happen again.