Trailing 6-4 4-4, Bulgarian world No.10 Dimitrov received treatment on his groin and hip region on Saturday at Pat Rafter Arena.
He left the court for more treatment and then attempted to play on before retiring citing left hip pain to send the 23-year-old into his fourth ATP final.
"You just want to win, but not like that. Hopefully Grigor is fine," Lehecka said.
"Hopefully he'll be ready for Melbourne. I don't know if it's something serious or not.
"I just felt in the last two points he made, he couldn't move. Something clicked, or I don't know what happened."
Dimitrov, a former world No.3, purred to a drought-breaking title a year ago to spark his return to the top 10 and again looked in fine touch in the steamy Queensland conditions.
A fourth ATP singles final for — Brisbane International (@BrisbaneTennis) @jirilehecka beckons, and it's any wonder given how comfortable he feels playing in Australia.We love watching you do your thing, Jiri, best of luck tomorrow!#BrisbaneTennis pic.twitter.com/bYzIg0K5t8January 4, 2025
He now has one week to recover before the Australian Open, while Lehecka is in familiar territory after claiming his first and only title in Adelaide last year.
Big servers Giovanni Mpetshi Perricard and Reilly Opelka, who beat Novak Djokovic on Friday night, will duel later on Saturday for the right to face Lehecka in the final.
The Czech won't have much time to watch though, scheduled to play a doubles semi-final against Mpetshi Perricard and Nicolas Jarry that could see the pair play into the early hours of Sunday's finals day.
"I'm used to going to bed late, there won't be a big change," Lehecka smiled.
"I'm the type of guy that when I sign for doubles, I want to play until the end.
"That's why I don't play doubles that often. When I'm not sure or I'm not convinced that I would finish the game, I'd rather not to play than to pull out end of second round."
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