There were few things more second eleven than counterattacking with excessive force. Hence, the shots were only to buy time. (Justina Robson, Selling Out, 2008.)
In context, it's clear that counterattacking with excessive force is something that one should not do. “Second eleven” is an adjectival phrase that qualifies something as inferior in some way.
In what way, precisely, is “second eleven” inferior? A web search suggests that this is about second-rate sports teams, though I don't fully understand the nuances of what it means for a cricket team to be “second XI”. But does “second eleven” necessarily mean weaker? In the context of the novel, either “gauche” or “having the potential to trigger a war” seems more plausible.
In addition to understanding the exact nuance of the meaning, I'm curious where and when this expression would be used outside of a sport context.
Best Answer
"Second eleven" would never be used outside a sports context - except as a metaphor, in which case it is common. A school, or club, or other sporting organisation, will have a First Eleven in a sport, who are the best team they can field. They will also have a Second Eleven, who are just as keen but less skilled, and possibly a Third and Fourth Eleven. ('Eleven' has no mystic significance, but as it applies in football and cricket as well as other less-known sports, it is often used to generalise. The company's First Eleven would be the best employees they can provide in the field under discussion, who are as likely to be contract negotiators as the literal footballers; the company's First Fifteen in either England or France would probably be rugby players, which makes it a less understandable metaphor.)
So second eleven as an adjective means 'not up to the standards of the best available'. There may be a further nuance, in that the Second Eleven (in sports) is often where you find those who have mastered the physical skills necessary but not fully understood the tactics of the game, which would suit your context; but I wouldn't say that's widely applicable, let alone universally agreed.