What does the cryptic crossword clue "Young swimmer to plead being injured (7)" mean?

The definition is "Young swimmer". The wordplay uses an anagram. anagram of TO + PLEAD = TADPOLE; definition: "Young swimmer" The answer is TADPOLE.

Young swimmer to plead being injured (7)

Guardian Cryptic #29148 | 28 Across | 2023-08-14 flower