It was in the corresponding round last season that the veteran Hawthorn defender tore his hamstring against West Coast, relegating him to the sidelines for the entire finals series.
Up until that point, Guerra had enjoyed an outstanding 2012, but he ultimately missed the most important part of it – and his team missed him.
This year, the 31-year-old has done everything possible to ensure the disaster is not repeated, monitoring his training loads closely and sitting out matches when he is sore.
He aimed for – and has played – 16 home and away games, down on last year's 19, and his most recent rest was as recently as a fortnight ago, when he missed the win over Collingwood with a sore knee.
Although confident he will be fine against the Sydney Swans on Friday night, he admitted it would be impossible this week not to think back to what happened 12 months ago.
"You obviously think about it, because you play all year and you want to play finals," Guerra told AFL.com.au.
"But round 23 was my sixth game straight last season, so the body was a bit fatigued.
"This time I'll have only played the one game leading into round 23 after having the weekend off the week before, so hopefully that helps.
"Hopefully I don't have any sleepless nights about it this week."
Throughout this year, the damaging left-footer has continued to play strong and consistent football, showing no signs that the game is passing him by.
He has also ticked off two significant milestones, playing his 150th game for the Hawks in round 13, and making his 250th AFL appearance six weeks later.
But Guerra is not finished yet.
He has stated a desire to play on into a 15th season, and is hopeful of being awarded another contract.
"I'd definitely love to play again," Guerra said.
"If I can play another 15 or 16 games next year and hopefully have another crack at it, I'll be very happy with that.
"I think the next few weeks will determine how I go and whether I get another contract.
"But I feel as though I've had a good, consistent year, and there's no reason why I couldn't play on.
"If I can get one more year, that would be it for me after that, I'd say."
Before then, though, Guerra has another big mission to complete.
A member of the Hawks' 2008 premiership team, he is desperate to seize the opportunity to win another.
"To have won one was unbelievable, but once you get that one, you want more," he said.
"To be able to say I'm a two-time premiership player would be an unbelievable feeling and something I'd look back on in 10 to 20 years time and be very grateful for."
Twitter: @AFL_MarkM
