The reverse could then apply I guess. Players get injuries any old time so let's just make them do more, push harder. Why not do 10 trials, maybe 20. We could do 5 per week for all of January, after all players get injuries in training so it doesn't matter much does it.
The simple fact is it's more exposure to risk. The more exposure to that risk the greater the likelihood of injury. What is needed is exposure to risk when the benefits are likely to outweigh those risks. Trials are in my humble opinion a completely unnecessary risk. In this case Darcy is an experienced campaigner and would gain virtually nothing from playing a trial match, but the risks have been proven significant for nil return.