Bayern are already without several injured and suspended players including Kingsley Coman, Serge Gnabry and Matthijs de Ligt.
"Leroy has not trained with the team. He will now undergo an individual test later today to see if he can train with the team later today which is a condition to be included in the squad," Tuchel told a press conference.
"We will just have to wait and see. Hopefully he can make the squad and he can help us coming on from the bench."
Champions Bayern have their backs to the wall, trailing league leaders Bayer Leverkusen by eight points with 11 games left in the season.
The Bavarians, who have won the previous 11 league titles, also face Lazio in their Champions League Round of 16 return leg in Munich next week, having lost 1-0 in Italy.
Bayern last week announced they would part ways with Tuchel at the end of the season, with the coach having taken over in March 2023.
"We know our situation in the league and in the Champions League. It makes no sense looking months into the future and what could possibly happen," Tuchel said.
"It is about delivering tomorrow, winning the game, cutting the gap (to Leverkusen). That is all we can influence and that's where our energy will be directed to."
Tuchel, however, was unhappy with the timing of Bayern's announcement earlier this week that Max Eberl is taking over as head of sport, saying it was the third time the club's structure changed in the past 10 months, in reference to previous internal changes.
"And it is the third time just before a league game. We will try to keep the focus on the game," Tuchel said. "Tomorrow it's all about winning in Freiburg."
