The 24-year-old German chose to save tyres in Saturday's qualifying session instead of join the fight for pole position - and hopes this tactic can work for him from ninth on the grid.
Vettel was in 10th place after qualifying but was lifted to ninth thanks to Venezuelan Pastor Maldonado's 10-place penalty after crashing his Williams into luckless Mexican Sergio Perez's Sauber in final practice.
Vettel, who won from pole last year, said: "Well, it is Monaco! And so, some people say it might rain tomorrow (Sunday) so that would make a big difference, but nevertheless we have the possibility to start on the hard tyre and have a different kind of race to normal.
"Usually it's all about track position, but this time we start from P9 and we have some cars ahead, but it could be different after the first stops. So we will see what we can do."
His Red Bull team-mate Australian Mark Webber took the second Monaco pole position of his career on Saturday after clocking the second fastest time behind Michael Schumacher of Mercedes, who was penalised five places for a collision at the Spanish Grand Prix.
Vettel added: "Obviously we would have loved to have qualified at the front, with Mark, but after Q1, and in particular Q2, we saw that pole position was not really in reach for me. That's why we decided to go the other way and we will see what we can do tomorrow."
Vettel won last year with a one-stop strategy, but was uncertain if he could the same again this time.
He said: "I think it's always open here because you never know what is going to happen in the race.
"It's a long race and there could be a safety car. You might be able to catch up, or lose all your advantage over someone else. It really depends. I think it can be fairly open for everyone."
Vettel pins Monaco hopes on strategy gamble
Advertisement