The 22-year-old has made just five appearances this season and was forced to withdraw from the USMNT squad earlier this month as he continues to be dogged by complications arising from a hamstring injury sustained in the FA Cup Final on Aug. 1.
Lampard has previously said Chelsea are "still searching" to identify the best training programme to guard against Pulisic suffering ongoing fitness issues, which also restricted his game time at Borussia Dortmund prior to joining for £58 million last summer.
"Christian Pulisic is back into contention and fitness," Lampard told a news conference on Friday. "He's fit, ready to start is a question mark. It is hard to gauge match fitness.
"In training, times as they are with COVID, it is very hard to recreate match play in training because the rest of the players are preparing for games every three days and we didn't have any academy games that we could mix bubbles.
"So, every player, not just Christian, coming back from fitness, it is more difficult to get them ready to start games, so we will see."
With Spurs top of the table and Chelsea two points back in third, the stakes are raised when Lampard renews battle with Jose Mourinho, his former manager for two spells during his 13 years as a player in west London.
Despite the pair's long-standing relationship, Mourinho has aimed multiple digs at Lampard, including a touchline spat during their EFL Cup clash in September.
The pair traded barbs before Lampard added in his postmatch news conference that "I commented on the fact that he seemed to speak to the referee more than his players."
Last December when Chelsea beat Spurs 2-0 at the Tottenham Hotspur Stadium, Mourinho took a swipe at his counterpart by claiming his former club adopted "Antonio Conte's" 3-4-3 formation, referencing Lampard's predecessor.
But Lampard hit back, and said: "I'm not surprised by anything in management because I think we all have similar jobs to do and we all have to sit in these press conferences and we all have our personalities.
"I've got respect for Jose as a manager and that's just how it is. I didn't take any offence to the talk of 'Antonio Conte's system' or whatever. I play that system clearly a lot differently last year when we did play it to how Conte would have done. But Jose can have his opinions and it's not a problem. I've got respect for him and it's nothing contentious for me."
Lampard also confirmed a clause exists in Thiago Silva's contract to extend his stay at the club for another year if Chelsea choose to activate it.
The 36-year-old has impressed since arriving on a free transfer from Paris Saint-Germain in the summer, signing a one-year deal, leading to speculation he could stay beyond the end of the season.
"I've seen the reports and there's an option in Thiago's contract that we can look at as the season goes on," added Lampard. "Obviously the way he's playing at the minute, we're very happy so that's the end of it really. I'm surprised it's come out in that way."