Speaking to the Brackley Town web site after his debut, Frank said: "It has been an unreal week. One week ago I was still the manager and planning for the game against Boston even though I had stated my intention to stand down.
"The phone has rung a lot since and I was pleased to hear from Jon (Brackley manager Jon Brady). In fact, before I knew it I was signed on to play. I appreciated Jon's call and the chance to come here to play this afternoon. I have really enjoyed it today.
"I keep fairly fit. As a manager I tried to join in with training when I could and I get to the gym on alternate days. I played the full 90 minutes for Colwyn Bay against both Hyde and Stockport County recently, and I scored in both games. So I felt I was physically up to the challenge today."
He's since added another appearance on Tuesday, a 1-1 draw at North Ferriby, but he's not envisaging a long return as a player. "In the long run I see myself back in management and I am completing my UEFA 'A' licence.
"There is no rush. I am doing my media work as yesterday when I was working for Chelsea TV and I may get into some junior coaching work," he added.
Brady said of him after his debut: "I am full of praise. Frank was first class today both on the pitch and with the younger lads. He fitted in which is true testament to him. His desire and enthusiasm to play and to win are brilliant."
Sinclair was with Burnley for two and a half years and played over 100 times for us and, for a time was club captain. He was one of five summer signings in 2004 after Steve Cotterill became manager and stayed until February 2007 when he signed for Huddersfield, initially on loan.
He left with praise ringing in his ears from his manager. Cotterill, who had signed Steven Caldwell days earlier, said: "He hasn't been a minute's bother side he's been here. He has been first class. We'd like to wish him all the best from everybody here.
"He's been magnificent from the moment he walked through the door, from his first header against Everton in his first pre-season friendly, until the last game he played for us."