Slow bowler

A slow bowler was a type of bowler in the sport of cricket. The Fourth Doctor once imagined that he would have been a "great" slow bowler, following the successful use of spin on the TARDIS to kick an asteroid out of a gravity whirlpool. (DW: The Horns of Nimon)

Behind the scenes
The terms "slow" and "fast" are confusing in cricket, because of multiple meanings. They describe both the speed of the bowled ball, and the speed with which the bowler ends his over, or allotment of six balls. Given the emphasis in The Horns of Nimon on spin, it's assumed that the Fourth Doctor was using the term "slow bowler" as a rough synonym for spin bowler — that is, a ball in which emphasis is placed on the spin that it has, rather than the speed it achieves.