The England striker has experienced a quiet second-half of the season, having not been able to add to his goal tally of 15 over the last nine games.
And Lampard has told the 22-year-old he must work hard in training to break out of the slump.
"I think on Tammy's contract we're not at a critical level with it and I'll leave that between him and the club to discuss that side of it," Lampard told reporters on Zoom. "I don't think it's something in his mind now. It certainly shouldn't be.
"What needs to be in his mind now is these games we have coming up and how much he can give us on the pitch, whether he's coming on as a sub or starting games. He has had a really good season.
"He hasn't scored so much in the second half of the season and as a young player, it's always clear that when you have those periods there's only one way out of it and that's work and repetition in training and trying to make the most out of every moment you get.
"I just think that's where Tammy's at. The contract will hopefully look after itself. It's between him and the club. He just needs to focus on giving us that Tammy that we had earlier in the season, which was giving defenders so much of a problem in games and scoring regularly.
"It all came from how he was training and working through the week. You could see it through his demeanour in the week, which meant he could perform on the matchday. That's what he has to sustain all the time.
"Not just Tammy. It's a general rule. We get very excited with young talent - and rightly so. We've seen it this season and that's why I've tried to stay pretty grounded when I get asked a lot about the youth, particularly earlier in the season, because I felt it coming.
"It's really hard to come into the Premier League, at the level it's at, and sustain performances or be in the side all the time. There's competition, games are hard.
"Whether it's Tammy, whether it's Mason, whether it's Fikayo, whether it's Reece, they've all had periods of real input and playing regularly and periods where it's maybe not quite so much, in their own different ways.
"That's something we all have to be a bit calm with from the outside and expect that.
"The main thing from working behind the scenes is that they understand that and that they will have those little moments and not lose confidence. I'm always there to support them on that. But also they need to continue the work.
"That's the message for all young players, not just mine. I've been there, I know how hard it is to break through, but when you break through it's possibly harder to sustain it and move on to a different level, which top players do.
"All these younger players here potentially have it. A lot of it is in their hands at this point."