Kelly Sotherton admitted last night that she might be forced to forgo the chance of rectifying a perceived wrong and that her hopes of competing at the World Championships are in the balance.

The heptathlete, who took bronze two years ago behind Lyudmila Blonska, the drug cheat who has since been banned, said a foot injury had wrecked her preparations for Berlin in August. “If I'm not in top shape then I won't go to Berlin,” she said. “These are the last four years of my career and London 2012 is the goal. I won't risk anything.”

The memory of her third place in Japan in 2007 could fester in less hardy souls. Blonska was thrown out of the Olympics last summer after a second failed drugs test and is banned for life. It means that, as she prepares for her last World Championships, Sotherton may never know if her bronze should have been a silver.

“I'd like to think they'd retest the samples,” she said. “But if I focus on 2007 I'm not thinking about what I can do. Even if someone handed me the silver, people will remember me as the woman who got the bronze. It could consume you, but I don't want to be a bitter athlete because there are a lot of those who've lost to cheats.”

This is typical Sotherton. Unlike most of her peers, you ask a question and you get a candid reply. Yet the makeover she received to launch the Aviva World Trials was symptomatic of a more substantial change and, as she nursed her injury, she said laughter had become the best medicine. “I needed to change my personality in terms of my relation to my sport,” she said. “I put too much pressure on myself and for years I've been fighting myself. I needed to relax. Instead of getting tense in sessions or upset if things go wrong, I laugh them off and my coach [Aston Moore] laughs back. I'm having more fun now. I'm learning to love it again so it's not a chore.”

The pressure will be off if she does make it to Berlin because of her compatriot, Jessica Ennis. Sotherton is 32 and Ennis 23, but the fledgeling, once dubbed Tadpole by the adopted Brummie, has leapfrogged her to third in the all-time United Kingdom standings. After a nightmare year, in which she missed the Olympics, Ennis returned last month to score 6,587 points. Sotherton's best of 6,547 was set four years ago, but she is happy to sail under the radar.

“Everyone writes me off because of my age or because they think I don't perform,” Sotherton said. “Instead of wanting two British women to do well, they only want one or the other. Well, I think what Jessica's done is fantastic. I actually thought she might score more. She's the world leader now and probably will be when we go to the World Championships. That means the pressure's off me. I don't care what anybody else does. If I'm in decent shape, then I'll be a contender.

“At the last two majors I've scored 6,500-plus. That's not a shabby score, but I have not fulfilled my potential. Yes, I got an Olympic bronze medal, but I've never put it all together at the same time.”

In Beijing she admitted she was distracted when she saw Blonska carrying a phial into the stadium. She wondered if it was a masking agent or a stimulant. “Maybe it did put me off my long jump,” she said. “I was thinking, ‘What on earth are you doing?' But I think my problem was a technical fault. It can happen. Something can just go, like the yips in golf. I had it in the javelin. Well, not any more.”

The Commonwealth champion is up against it. She will compete at the Aviva World Trials and UK Championships in Birmingham between July 10 and 12 but has pulled out of a heptathlon in Germany this month. But with Blonska gone and Charles van Commenee, her former mentor, now head coach of UK Athletics, she cuts a more contented figure. “It's hard for me because I still see him as my old coach, but it's kind of an honour because he believes in me and that makes me believe in myself,” she said.