As a professional of over 14 years, Defoe knows a lot can change in football in 12 months.
This time last season Defoe was on top of the world. The striker had scored twice for England in three appearances and he had nailed down a first-team place at Spurs, where he found the net three times in his opening four matches.
Now the picture is quite different. The 30-year-old is yet to start a Barclays Premier League game and he did not feature against Moldova and Ukraine despite the absences of Wayne Rooney, Daniel Sturridge and Andy Carroll.
Defoe is desperate to make the cut for what would be his last World Cup, but the Tottenham forward knows his chances of making the plane to Rio - should England qualify - are not being helped by his lack of first-team action.
"It's important for me to play this year," the striker told Press Association Sport at a fundraising gala dinner for the Jermain Defoe Foundation.
"I want to play games because it's a World Cup year.
"Having gone to a World Cup, it's something you want to experience again as a player.
"It's the best thing ever, representing the country when the whole world is watching, so I understand the importance of actually playing in a World Cup year."
Roberto Soldado has repaid a chunk of his B£26million transfer fee by scoring four goals in his first five games since moving from Valencia.
Consequently, Defoe's Premier League game time this term consists of seven minutes at Crystal Palace, nine against Swansea and a 21-minute cameo in the north London derby.
The fact that Defoe cut short his summer holidays to spend two weeks in France with fitness guru Tiberius Darau only heightens his disappointment at not playing regularly.
"It's frustrating when you have worked really hard in pre-season," he said.
"A boxer trains for eight weeks before a fight and then on fight night he wants to be ready and perform, but he actually wants take part.
"I went away, worked hard and made sure I was fit. I felt sharp and stronger than ever so it's difficult when you are in and out of the team."