Pulisic has made just two substitute appearances for Chelsea since sustaining an ankle injury while away with USA in September.
The 23-year-old played 16 minutes in last week's Champions League win at Malmo and the final five minutes of Sunday's (AEDT) 1-1 draw with Burnley in the Premier League.
He came through those games unscathed and will now link up with his national team for their World Cup qualifiers against Mexico and Jamaica over the next eight days.
However, Tuchel has urged caution as Pulisic battles to overcome the persistent ankle problem that has restricted him to just four club appearances in 2021-22.
"I think you can see from the minutes he's had, then the questions of whether he's at his peak level are answered," Tuchel said.
"It will take time with Christian because he's been out for such a long time this season, but he is easing his way back in and is doing well.
"I hope that the US national team are responsible with him and they don't overuse him too much in the international fixture.
"Christian still feels a little bit of pain but of course, he absolutely wants to come back to full fitness and at his peak level of performance that he's shown before.
"It's a matter of managing the pain in his ankle, not a matter of a reinjury or anything like that. It's just that things are still a bit painful for him.
"He desperately wanted to come back and we need him back, because he's a big player for us.
"He's tried so hard when he's come on in recent games and it was a good start for him in Malmo, and then the 10 minutes or so he got against Burnley.
"I have to say, we are always a little worried when our players go away with the national team.
"It's out of our control but there is also a responsibility for Christian to not get carried away and try too much."
Pulisic has featured 81 times for Chelsea in all competitions since arriving from Borussia Dortmund ahead of the 2019-20 season, starting 53 of those games.
The 23-year-old has scored 18 goals and assisted 11 more across that period, a direct goal involvement tally of 29 that is bettered only by Mason Mount (35) and Tammy Abraham (38) among Chelsea players.
He is expected to add to his 40 caps for USA in their upcoming double-header and, while Tuchel remains apprehensive, he hopes Pulisic will return to Stamford Bridge fitter.
"I understand that playing for your country is emotional and he will want to give everything to help his country win a super important match," Tuchel said.
"Hopefully the minutes will elevate him for when he returns to us and he will be in a better place physically."