Time Lords don't have any innate ability to shrink. However, technology or accidents that can shrink humans can also shrink Time Lords, as we've seen many times. For example:
- A TARDIS accident shrank the First Doctor and Susan along with Barbara and Ian (and the TARDIS) in "Planet of Giants".
- The Master's Tissue Compression Eliminator shrank (and killed) Time Lords in "The Deadly Assassin", and while experimenting with it he accidentally shrank himself in "Planet of Fire".
- The Teselecta's compression field shrank the Eleventh Doctor just like its crewmembers in "Let's Kill Hitler".
- The Aristotle's molecular nanoscaler shrank the Twelfth Doctor along with Clara in "Into the Dalek".