The six Scottish Premiership players likely to attract most transfer speculation this summer

The summer transfer window officially opens on June 10. Several clubs have been active already, including John Souttar's move from Rangers to Hearts and Hibs' capture of Scotland goalkeeper David Marshall. Celtic converted Japanese striker Daizen Maeda’s loan into a permanent deal and Hearts signed Alan Forrest from Livingston. The market will get busier over the next few weeks as the speculation over players' futures intensifies.

Calvin Bassey has impressed for Nigeria in recent friendlies. Aston Villa manager Steven Gerrard is keen on a reunion with the defender. Bassy moved to Rangers from Leicester City for £230,000 two years ago. He impressed in Rangers' Europa League final win against Borussia Dortmund.

Liverpool are keen on signing Aberdeen's 18-year-old right-back Calvin Ramsay. Ramsay was named Young Scottish Player of the Year. Leeds United, West Ham United and Bologna are also interested in Ramsay's signature.

Ryan Porteous is entering the final year of his contract at Hibs. He has attracted interest from Millwall and several other English Championship clubs. New Hib's boss Lee Johnson wants to keep Portese as an integral part of the team next season.

Ross County striker Regan Charles-Cook is the most transfer-able player in Scottish Premiership. He scored 13 goals last season and is up for PFA Scotland Player of the Year award. Charles Cook has been linked with Hibs and English League One outfit Fleetwood Town.

Joe Aribo has just one year left on his current contract at Rangers. The Nigerian international midfielder has attracted interest from Crystal Palace.

Lewis Ferguson is open to a move to English football. The Aberdeen midfielder has two years left on his contract at Pittodrie. Watford tried to sign him last year but the Dons rejected their offer. Cagliari's relegation makes them less likely to land him this summer.