Which players are attracting attention in Europe's biggest leagues? Scouting Spotlight looks at three players each week whose performances are making headlines ...
Aaron Martin -- Espanyol
After making his debut in October 2016, Martin has earned a regular starting spot at Espanyol and attracted admirers across Europe with his impressive performances. The left-back has won three caps for Spain Under-21s but was overlooked for the European Championship squad in the summer.
An agile, tenacious full-back, Martin's tactical maturity has caught the eye at Espanyol. His positioning is sound, along with his awareness to provide cover for teammates, but there are occasions when he can leave himself exposed by snapping into challenges.
He was lucky to avoid being punished for this tendency in the recent 2-0 defeat to Real Madrid, while some sloppy passing also put his teammates under pressure.
Martin's pace allows him to atone for errors and occasional over-exuberance, though. He likes to roam forward to support the attack, but is quick to track back and prioritise his defensive duties. He often looks to steal the ball off the toes of his opponent before they have time to bring it under control.
Martin has maintained his steady progress at Espanyol this season despite a mixed start to the campaign for Quique Sanchez Flores's side.
Along with most of the team he struggled in the 5-0 derby thrashing by Barcelona but, apart from that heavy loss and the 2-0 defeat to Real Madrid, Espanyol have conceded only four goals in their other six fixtures.
Despite his early promise, the 20-year-old will hope to improve on his contribution in the final third - he is yet to claim a goal or an assist in 38 La Liga appearances.
However, he is still capable of producing devastating deliveries, as he demonstrated with a wonderful cross for Gerard Moreno against Levante at the weekend, only to find the striker had strayed into an offside position.
Where would he fit in?
Manchester United have been strongly linked with a move, despite the youngster signing a new contract at Espanyol earlier this year.
With Luke Shaw still struggling for form and fitness, Jose Mourinho has reportedly identified Martin as a long-term solution at left-back and sent a scouting team to report back on Espanyol's 0-0 draw with Levante last Friday.
Despite the result, they should have been encouraged by what they saw, although United may be reluctant to meet Martin's €40 million buyout clause.
Leon Goretzka -- Schalke
Goretzka is already a familiar name around Europe thanks to his dominating Bundesliga displays for Schalke. With his contract expiring at the end of the season, and foreign clubs allowed to open negotiations from Jan. 1, the race for his signature is reaching a critical point.
A versatile, goal scoring midfielder, Goretzka is an imposing presence in the centre of the pitch. He is comfortable screening the defence and strong in the tackle, while presenting a threat going forward with his driving runs and shooting ability from distance. At 6-foot-2, he is also effective at both defending and attacking set-pieces.
His passing skills have contributed to his reputation as a complete player at just 22 years of age. Goretzka will often elect to stretch the play or make the incisive pass after spotting a teammate's run, sliding the ball between defenders or scooping it over the top.
His tactical flexibility has seen him adopt a number of different roles at Schalke, with his impressive range of attributes allowing him to play as a two or three in the middle alongside Nabil Bentaleb and Max Meyer.
Goretzka's form is likely to secure him a big move at the end of the season when his Schalke contract expires. He has claimed three goals in the Bundesliga so far, including a well-taken penalty in a 2-0 victory over Hertha Berlin at the weekend, and has delivered a string of scintillating displays for the national team.
The former Bochum midfielder made his debut for Germany in the warm-up friendlies before the 2014 World Cup, but missed out on a place in the final squad. He starred in the Confederations Cup over the summer, however, scoring twice inside the first 10 minutes in a 4-1 win against Mexico. Goretzka has since taken his tally to six strikes in 12 caps to suggest he will be on the plane to Russia.
Where would he fit in?
Given his versatility, Goretzka would solve problems at a number of top clubs, and it is no surprise to see the likes of Bayern Munich, Juventus, Liverpool and Manchester United all expressing an interest in his services.
Bayern are reported to be the frontrunners to secure his signature on a free transfer this summer, but Schalke may decide to cash in when the transfer window opens in January.
Hirving Lozano -- PSV Eindhoven
Having moved from Mexico to Europe in the summer, Lozano has settled instantly at PSV Eindhoven, prompting speculation that he could be on the move again soon.
Starting on the left side of PSV's fluid front three, Lozano is a dynamic inverted winger who likes to run at defenders before cutting inside in search of goal scoring opportunities on his favoured right foot. He is capable of exploiting pockets of space in the final third, using his speed and off-the-ball movement to find gaps in the defensive line.
Despite his excellent form in front of goal, his shooting can be rushed at times, while the 22-year-old can also dribble himself into trouble. His decision-making should improve as he continues to develop his game at PSV, but Phillip Cocu will be more concerned with nurturing his natural instinct around the box.
Lozano's performances have been a key factor in PSV opening up a five-point gap at the top of the Eredivisie, with six goals and two assists in his first eight matches. There have been a variety of different strikes, from a solo effort on his debut against AZ Alkmaar, to bundled backpost finishes and a header in the forward's last outing against Willem II.
Lozano is also the great hope of the Mexico national team and will be Russia-bound for the World Cup next year after scoring five times in 22 caps following his breakthrough at Pachuca.
Where would he fit in?
There has been talk of Arsenal plotting a £30m move for the forward as they look to replace Alexis Sanchez, who seems certain to depart when his contract expires in June, if not in the January transfer window.
Although a different type of player, it's easy to envisage Lozano adopting a similar role to the Chilean in the Gunners' front line. Starting nominally on the left, his game is centred on cutting inside to create chances and profit from others fashioned by teammates.