Prior to taking a break from the sport, four-time grand slam champion Osaka revealed she had suffered "long bouts of depression" since winning the US Open in 2018.
The 23-year-old said this month she wants "some level of privacy and empathy" from the media when she returns to action and but also discussed her excitement at playing in a "dream" Olympics.
Former Wimbledon champion Cash insists Osaka has the game to triumph but feels it is a tougher task now given her main opponents are coming off two grand slams in quick succession.
"Yeah, she said [she was taking] time out – it's hard to know if she's going to be match hardened," Cash said to Stats Perform.
"I think that's the thing about playing Wimbledon, the grass court season. Are you match toughened?
"That goes a huge, huge way [to achieving success, and not having that] is putting yourself under pressure and especially under those circumstances if it's for a gold medal."
Cash feels the quality and depth of opposition in the women's draw is another obstacle in Osaka's bid for gold.
Wimbledon winner Ash Barty, beaten finalist Karolina Pliskova, former French Open champion Iga Swiatek and Aryna Sabalenka are scheduled to be among the highest-ranked competitors for Osaka at the Olympics.
Cash added: "There are a lot of good players too. Going back onto the hard court, I think that favours certain players who hit the ball hard like Sabalenka for instance.
"But there's 30 girls who really do think they can win a gold medal there and I think that's true.
"So it's very hard to predict who will win, obviously Japan want Osaka to win, but with her being out, I think it's less likely than in a normal circumstance where she's playing matches.
"But she's such a talent that she really could come out there and blast players away, so I wouldn't put it past her."