Per Goal's Peter Hanson, Rabiot is in the final year of his contract with PSG and interested Barca in the summer ahead of reports linking him with Chelsea, Juve and Bayern Munich.
Tuchel evidently wants the midfielder to stay put, though. He told RMC Sport (h/t Hanson):
"I love working with Rabiot. I really like Adrien, he had a difficult situation when he voluntarily missed the World Cup, but his effort with the team has been maximum. He has not missed any training.
"He can be adapted to any system, and if he is physically well he is essential for our approach.
"He has great potential and is a player trained in the club. It is very important to have footballers of this nature."
After some disappointing form toward the end of last season, Rabiot was not named in Didier Deschamps' France squad for the FIFA World Cup.
ESPN FC's Jonathan Johnson had expected his exclusion:
Jonathan Johnson @Jon_LeGossip
I understand there will be a lot of surprise re: Rabiot being left out by Didier Deschamps. However, if you have really watched PSG post-Madrid, this will not be such a shock. He has dropped off massively & I have been suggesting that this could happen for weeks. #EDF #LesBleus
The 23-year-old was to be placed on the standby list but refused to be included as a reserve.
Rabiot's form may not have warranted selection for the national team this summer, but he's an important player for PSG and could become one for France.
The Frenchman is not only an excellent distributor of the ball, he also excels in winning it back from the opposition, per Scouted Football:
Scouted Football @ScoutedFtbl
Most successful tackles in Ligue 1 this season - success rate metric: 100.0% • 🇫🇷 Adrien Rabiot (23) 94.7% • 🇨🇮 Ibrahim Sangaré (20) 89.5% • 🇫🇷 Lucas Tousart (21) 88.2% • 🇫🇷 Sofiane Alakouch (20) 87.5% • 🇫🇷 Vincent Manceau Hungry. Minimum 12 tackles. https://t.co/L8bbsBYIaa
Rabiot's attitude was understandably called into question, and it seems he has room to grow in that regard, but it's clear he has plenty of ability.
Players of his talent aren't often available for free, which he will be next summer if he does not sign a new deal at the Parc des Princes in the meantime, so it's no surprise there are a host of top clubs monitoring the situation.
Tuchel's admiration of him is clear, not only from his comments but by the fact Rabiot has completed 90 minutes in all five of PSG's matches this season.
Making him feel wanted could help convince him to stay put, which would be a boost for PSG.