And Steve Hernandez has been named the club’s new goalkeeper coach.
Former Chelsea defender Sinclair had stepped into the position from his role as U16 coach on a caretaker basis to assist Gary McSheffrey over the last month while Academy goalkeeper coach Hernandez took on the role at senior level following the departure of Paul Gerrard in November.
And after McSheffrey was handed the reins on a permanent basis, both men committed their futures at senior level also.
A former Jamaica international, Sinclair represented his nation in the 1998 World Cup.
The 50-year-old played in the Premier League for Chelsea and Leicester City, winning the FA Cup, League Cup and UEFA Cup Winners’ Cup during his playing career. He also had spells with Burnley, Huddersfield Town and Lincoln City before moving into non-league football.
He formally joined Rovers in October to lead the U16 coaching.
Hernandez has been on the Rovers age group staff for several years and became head of Academy goalkeeping.
He was on the books of Sheffield United as a youngster and moved into coaching after being released as an 18-year-old.