Thomas Tuchel believes Chelsea must consider N'Golo Kante's poor injury record when they discuss a new contract with the France midfielder.
Kante has been crucial to Premier League, Champions League and Europa League wins since arriving at Chelsea in 2016, earning a reputation as one of the world's finest midfield enforcers.
But the 2018 World Cup winner has been beset by injury woes in recent seasons, and was ruled out for "several weeks" after suffering a hamstring injury ahead of last week's 3-0 defeat at Leeds United.
Kante made at least 34 Premier League starts in each of his first three seasons with Chelsea, but has failed to start more than 24 games in each of his last three full campaigns.
With the 31-year-old having entered the final 12 months of his contract with the club, Tuchel acknowledges his fitness record is a long-term concern.
"You have to consider everything that is on the table and on the table is his potential, on the table is his influence, and his quality," Tuchel said ahead of Saturday's home league clash with Leicester City.
"But also on the table, of course, is his age, his salary and his injury rate. From there you build a whole picture and try to find a solution."
Chelsea have taken four points from their first three games of the Premier League season, and sorely missed Kante's defensive discipline when they were torn apart at Elland Road last time out.
And Tuchel believes the midfielder's lack of availability makes it difficult for Chelsea to maintain a genuine title bid, adding: "This is a key question.
"We try to but it's much more difficult because you see the impact he has, you see the impact in the goals that we concede, the amount of goals we score, the amount of points that we have, the amount of goals he makes.
"He makes players simply better around him. He gives something that is very unique and don't forget, he also installs confidence that you cannot measure. That's why he is a key player.
"But for the key players, it is super important to be on the pitch and to have that impact and be in the rhythm.
"You can count the matches that he is missing, but what about the first two, three or four matches where he needs to re-find rhythm? Nobody is counting these matches, so maybe in real life it is even more than just the matches he is missing.
"He comes back for the first match from the bench and maybe a second from the bench, and then the third one still struggling with confidence and rhythm.
"This is basically the story and, yes, we have huge hopes we can turn things around, but this was a bad start."