Germany international Reus has been out of action since being withdrawn in the 44th minute of BVB's 6-2 win over Bayer Leverkusen on Matchday 23, and also missed the first 11 games of the current Bundesliga campaign.
Watch: Marco Reus' journey to stardom
"He's [Reus] training with the ball and feels good, but I'd urge caution," Tuchel explained. "It's the most complicated and decisive stage of the season. If we weren't in April, I'd take things slowly. I'm not yet sure what to do for the best."