Blackwell's career will come full circle on Saturday when she returns to Sydney's Drummoyne Oval for the semi-final against Brisbane, the site of her domestic cricket debut for NSW against Queensland in 2001-02.

The 35-year-old called stumps on her international and NSW Breakers career last summer, with her 12 Tests, 144 one-day internationals and 95 Twenty20s making for a record 251 games in the green and gold.

Blackwell scored more than 5,000 runs for Australia across all three forms and has been involved in the game long enough to see it grow to the point she believes this weekend's double-header semi-finals could be sold out.

But off-contract with the Thunder at the end of the summer, Blackwell is yet to decide if she'll press on for a 19th season next year.

"It could always be your last couple of weeks, it could be anyone's," Blackwell told AAP.

"I guess for me in my stage in my career, that's a reasonable consideration that it could be my last couple of games..

"But I think for me it's been a bit more challenging the decision making because I've been playing well. I'm going to make those decisions at the end of the season."

The Thunder were barely challenged for a finals spot in their run to the semis, with their loss to the Heat last week one of just four in the 14-round season as they finished second.

Blackwell herself is in form, having hit scores of 66 not out and 28 in her past two games with the Thunder's batting line up one of the strongest in the competition.

She's also taken a new approach with her captaincy, putting more onus on younger players to step up strategically as the next wave of NSW stars come through the Thunder ranks.

"I've enjoyed the captaincy and seeing the growth in my players," Blackwell, who now sits on the Cricket NSW board, said.

"Because I didn't play a lot of cricket coming into this, I feel really fresh still after 14 games and I feel really comfortable with my game.

"It was always the intention to peak at the back-end of the season."

Australian Associated Press