Sean Jefferson has left his role as director of partnerships at Manchester United after almost six years with the English soccer giants.

In a post on LinkedIn, he said he is leaving the Premier League club to “explore a new challenge.”

Jefferson joined United in June 2017 and was a key figure in the club’s commercial team.

The senior executive was responsible for managing relationships with 25 global partners and played a key role in an area that has become a major revenue source for United.

In the team’s most recent figures, for the second quarter of the year, commercial revenue was up 22.2% to £78.7 million ($98.3 million), attributed primarily to a £15.2-million increase in sponsorship income through the Tezos training kit deal struck last year.

Before joining United, Jefferson spent 10 years at global media agency Mindshare and two years at international drinks giant Diageo.

Jefferson said on LinkedIn: “It was an absolute privilege to work at such a great club. Before I joined in June 2017, I knew it was the biggest and most high-profile club on the planet and a commercial powerhouse. It still is, and always will be. But the actual experience, on the inside, was phenomenal.
“It’s been an honor to work with so many great people across the club, a joy to collaborate (and renew with) so many wonderful partners, to build an innovative and measurably effective partnerships model.
“But, the time was right for me to explore a new challenge and we agreed I can move on with the blessing and very positive support of the club.”

Jefferson departs while the club are still searching for a new primary shirt sponsor after agreeing to terminate their long-term deal with global technology firm TeamViewer three years early.

TeamViewer’s contract is worth around £47 million per year.

Jefferson is also leaving United amid uncertainty surrounding a potential sale of the team, with the Glazer family having announced in November that they were exploring outside investment for the club.

It is thought that the American owners are seeking in the region of £5 billion to £6 billion for a full sale, with a minority sale also a possibility.

Qatari Shiekh Hamad bin Jassim bin Jaber Al Thani and the British Ineos owner Sir Jim Ratcliffe are both reported to have submitted second bids for a full takeover.