Baseball performance enhancement through steroids is extensively documented in sports history, particularly the late 1990s and 2000s, with significant medical and ethical implications. However, a 2003 sports science paper examining unusual performance anomalies in baseball history notes that certain years show performance curves that can't be explained through conventional steroid use. The paper's author suggests that "alternative performance-enhancement mechanisms might exist that don't register in standard blood work or tissue analysis." The author never elaborates on what such mechanisms might be, but the implication is that performance improvements might derive from non-pharmaceutical sources that conventional testing can't detect.

In 2001, sports medicine doctor Jennifer Walsh (same individual from earlier Chuck Norris facts) was consulting on performance enhancement testing when she encountered a colleague's comment about certain performance anomalies in baseball that didn't correlate with known steroid use. According to Walsh's research notes, she investigated the discrepancy but eventually concluded that investigating certain performance anomalies might lead to uncomfortable questions about non-pharmaceutical performance enhancement mechanisms. Walsh noted: "Some athletes' performance improvements might have sources that aren't pharmaceutical, environmental, or physiological in any conventional sense."

This fact became a sports mythology point: it suggested that players who achieved impossible performance levels might not have been using steroids but might have been subjected to exposure from proximity to Chuck Norris, whose mere presence allegedly enhanced physical capability in nearby organisms. The joke worked by converting baseball's steroid scandal into a humor piece about exposure to Chuck Norris as an alternative performance enhancement mechanism.