Tottenham might have had Ross Barkley in their side for Saturday's Premier League clash against Chelsea, but he is instead in contention to feature for the Blues at Wembley.
Barkley was strongly linked with a Spurs switch in 2017 but the club appeared to baulk at Everton's asking price, with Chelsea swooping in for a cut-price £15million deal in January.
Although the midfielder initially struggled to make an impact under Antonio Conte, the Italian's successor and compatriot Maurizio Sarri has helped Barkley take his game to the next level.
Sarri has dubbed Barkley a "complete" player and his development has been so rapid he was preferred to regular starters Dele Alli and Jesse Lingard for England's Nations League decider against Croatia last weekend.
Here, we assess Opta numbers to examine how Barkley has improved to become one of the Premier League's top creative players in the 2018-19 season so far.
Greater control of possession
One of the areas where Barkley had to step up his game was decision-making and playing the right pass, as he previously gave the ball away far too often.
During the 24-year-old's last full season at Everton saw him complete 82.5 per cent of his passes, a figure that has radically improved in 2018-19 at Chelsea.
While it should be noted he is surrounded by higher quality players at Stamford Bridge, Barkley's new passing accuracy record of 91.98 is elite level and shows he is adopting Sarri's ideals.
The Chelsea boss prioritises possession above all else, with Barkley evidently taking this philosophy on board. He has only attempted eight dribbles in the Premier League this season, completing half of them.
What is particularly impressive about Barkley's distribution statistics is how he continues to reliably keep the ball in opposition territory, completing 91.82 per cent of passes in the attacking half.
This shows he can be increasingly trusted to make the right decisions on the ball, not wasting possession and ensuring the Blues keep up their pressure in the final third.
Adding creativity and goals from midfield
Although Chelsea made a strong start under Sarri, there was something missing in the middle of the park where he fielded Jorginho and N'Golo Kante with Mateo Kovacic, who joined on loan from Real Madrid.
Kante is one of the world's finest defensive midfielders but shooting is not his strength, while Kovacic and Jorginho are not goalscorers either. Sarri lacked a Marek Hamsik-style figure, the Slovakia star who regularly got in the box to score for his Napoli side.
The early signs are Barkley could become that man as he has already recorded three goals and three assists in the Premier League, despite only starting five games in the competition this term.
By contrast, Spurs midfielder Alli - whose 468 minutes in the league narrowly outstrips Barkley's 463 despite his injury issues - has provided one goal and no assists in England's top flight, showing why Gareth Southgate opted for the Liverpudlian against Croatia.
Barkley only scored five times in his last full Everton season despite making 36 appearances in the Premier League, suggesting he has increased his threat in front of goal.
If he can maintain the performance levels he has shown in recent weeks, Chelsea's chances of staying in touch with Premier League leaders Manchester City will be boosted.
Defensive work to do
Despite Sarri's description of Barkley as "complete", it is clear there is one obvious area of development he can work on in the coming weeks and months.
Defending has never been among Barkley's strengths but he will need to increase some fairly mediocre statistics if he is to be regarded as an all-round performer in the middle of the park.
Barkley has won 50 per cent of his tackles attempted in the Premier League, while he has come out on top in 46.3 per cent of the duels he has contested.
Again, the Opta data shows Barkley has improved from his 2016-17 campaign for Everton, where his duel success stood at just 40.05 per cent.
But comparing him to Saturday's opponent Alli - two years his junior at 22 - proves Barkley must learn to channel his combative nature in a more fruitful manner.
Alli's 12 tackles and nine interceptions in the Premier League this season dwarf Barkley's six tackles and two interceptions, even though they play similar roles for their clubs. Barkley has also conceded eight fouls to Alli's six.
But the England midfielder is developing rapidly under Sarri and it would be no surprise to see him improve those defensive statistics over the course of the season.
