Chelsea's Jose Mourinho rejects blaze a trail through Premier League
As Chelsea ponder the nine points separating them from runaway leaders Manchester City, they must wonder how different the table might look had former cast-offs Kevin De Bruyne and Mohamed Salah still been in their team.
This season's standout players both exited Stamford Bridge after frustrating periods under former manager Jose Mourinho, who recognised but failed to realise their potential.
De Bruyne and Salah each refocused their careers elsewhere in Europe before arriving back in the Premier League bristling with intent - at City and Liverpool respectively.
De Bruyne, in particular, has been instrumental in City's astonishing start to a season in which they have scored 52 goals in all competitions.
The Belgian is no one-season wonder, however, and over the past five years only Barcelona's Lionel Messi has recorded more assists in Europe's top five leagues, with De Bruyne's performances at City turbo-charged by Pep Guardiola's arrival as manager.
On Saturday, he scored City's opener in the 3-1 win over Arsenal, exchanging passes with Fernandinho before unleashing an angled drive into the bottom corner.
De Bruyne's performances make Mourinho's decision to ditch him from Chelsea after just 33 games in two years all the more questionable, although the Portuguese insisted he had his reasons.
"He was not training very well. He was saying: 'I can't give you more. This is just my way'," said Mourinho when asked about the departure.
The Egyptian failed to make an impact in 12 months under Mourinho, moving to Fiorentina on loan as a makeweight in a deal in which Juan Cuadrado, another soon-to-be Chelsea misfit, headed the other way.
Salah's switch proved the making of him and, after arriving at Anfield via Roma, the 25-year-old's impact this season has been great. On Saturday he scored his 11th and 12th goals in 17 games, the best striking record by anyone at the club since Michael Owen in 2001-02, who also reached his 12-goal mark on Nov. 4 that season.
Not surprisingly, Salah's rich scoring seam is delighting manager Jurgen Klopp.
"I didn't think if he can score 12 goals or whatever in 17 games," the Liverpool coach said.
" But I hope he's not finished now!"
Owen ended with 28 goals in 43 appearances in 2002 and Salah, who needs just three more to beat last season's Liverpool top scorer, Philippe Coutinho, could yet join another Reds great, Luis Suarez, as one of the few strikers to notch 30 goals in a season.
There is little doubt the presence of De Bruyne and Salah in Chelsea's ranks would have improved their early results this season.
But perhaps both needed the disappointment of their Chelsea rejections to reach their current heights.
Watford's Nathaniel Chalobah is another who quit the club this year only to be rewarded with an England call-up. Tammy Abraham, on loan at Swansea City, also made national manager Gareth Southgate's squad after failing to break through at Stamford Bridge.
Watford's Nathaniel Chalobah speaks to referee Anthony TaylorReuters
Chelsea manager Antonio Conte is insistent that under his regime, all the club's young talent has a pathway to the first team and points to his own record as Juventus manager where he nurtured Paul Pogba, who is now playing under Mourinho at Manchester United.
But for all Conte's fine words, it is clear that De Bruyne and Salah were allowed to slip through the net at Chelsea, a mistake so costly it may stop the champions from successfully defending their title.