I agree put in those terms to loose a player for 5 wins would be a disaster, however fortunately from a statistical perspective the statement is flawed. Injuries fortunately happen relatively rarely but do happen.
To say one injury over a very short period of observation, one day, is a bad day for British tennis; could, on a message board where pedantic analysis of any tip bit or comment around British tennis is the "plat du jour" result in a feeding frenzy of harsh critique. If that player were Andy, Kyle, Joko, Hev or Katie S; and the injury carer threatening, I agree trade against 5 wins, a bad day for British tennis.
No disrespect to Tara but she still has a bit to do to make my heart sink in the same way. Obviously I hope it is a precautionary withdrawal and she is able to get back to training with a focus on conditioning, a bit like Evo she is approaching an age where it is essential to leave no stone unturned to get into the shape of her life and give her the best opportunity of battling her way back up the rankings and maximising her obvious ability.