Sidebottom was named as our Player of the Month on the first day of the Championship match with Kent and put the award down to hard work in the close season.
He said: "I didn't play any club cricket in the winter and stayed at home to work on my fitness.
"It seems to be paying off because I've started the season really well. I'm enjoying my cricket, feel relaxed and am in a very good rhythm at the moment."
Director of Cricket Mick Newell said: "Ryan has started the season in terrific form and has been our outstanding bowler in all competitions.
"I think he?s already improved on his performances last season and has got the ball swinging at a decent pace.
"He?s shouldered the extra workload in the past few games with the injuries to our other seamers and I?m sure the squad will be delighted for him as he?s a popular man in the dressing room and a terrific team player."
The 27-year-old had more reason to celebrate at the close as he finished with 5-61 in the visitors' first innings, his first five-wicket haul of the season.
He added: "We've not had much luck with injuries so far but we're digging deep and are working hard for each other.
"I got the right end to bowl from, found my rhythm and got the edges. Hopefully we can build a decent lead now and put ourselves in a position to win the game."
Sidebottom received his award from PKF Partner-in-Charge Neil Gray during the lunch interval. At the same time Stephen Fleming and Graeme Swann received their county caps from Jason Gallian.
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