The Sacramento Kings have agreed to an extension with Harrison Barnes for 3 years and $54 million, according to ESPN’s Adrian Wojnarowski. The average of $18 million per season is higher than many Kings fans were hoping, while some fans didn’t want Barnes to return at all, instead hoping for a more significant upgrade to the team. Sacramento Kings forward Harrison Barnes – a key part of the franchise’s rise into Western Conference contention – has agreed on a new three-year, $54 million contract extension, his agent Jeff Schwartz of @Excelbasketball tells ESPN. pic.twitter.com/JCT4RUayt7 — Adrian Wojnarowski (@wojespn) June 30,…