The German centre-back, whose contract expires in the summer, has looked likely to leave the Blues for some time with suggestions the club are reluctant to meet his wage demands.
Now it has been apparently revealed by a report from Football Insider that the 28-year-old has leapt closer to the exit after being 'offered less than' his young teammate Mason Mount.
There have been rumours surrounding the England midfielder, who is currently one of the west London outfit's lowest earners, receiving a new deal that would at least double his £75,000-a-week wage.
There's little doubt the 22-year-old deserves to be rewarded with improved terms. Mount has scored in four consecutive games as of Thursday's draw against Everton and experienced a stellar year for club and country.
However, despite a contract improvement for Mount being inevitable, it's claimed Rudiger has been disgruntled by the news that the Chelsea starlet would be on a better income than him.
The Germany international has by no means been short of interest from other clubs as his contract expiry date draws closer, with Real Madrid said to be leading the charge alongside Paris Saint-Germain and Bayern Munich.
In fact, it's understood the LaLiga club are happy to pay Rudiger's desired £200,000-per-week, overtaking Chelsea's offer of £140,000.
However Ralf Rangnick's Manchester United have now joined in the race for the defender, and Rudiger's fellow countryman has a notable advantage over the rest of the chasing pack.
The centre-back's agent, Sahr Senesie, has a close working relationship with the Red Devils boss that began during the 63-year-old coach's time at RB Leipzig and Salzburg.
So the United interim manager's connection to Rudiger may well aid him in his efforts to improve his team's inconsistent back line.
Rudiger has played 170 games for Chelsea and has been a key part of Chelsea's success so far this campaign, starting every Premier League game bar one.
The Champions League winner's fortunes at Stamford Bridge turned under now-boss Thomas Tuchel, with the defender pinning his desire to stay at the club last campaign on the German.
"Thomas Tuchel came and the rest is history," Rudiger told Sky Sports, "He opened a new door… he played a big role."
However, fast forward a few months and the Chelsea star looks increasingly likely to be leaving the London club behind, now that Rangnick is waiting to swoop him away.