Not at all. Any muscle you have can be conditioned to be flexible. Unless you're some sort of Cirque du Soleil contortionist, muscle shouldn't reduce your flexibility, as long as you do full ROM.
Just afew thoughts though, because I also lift weights in addition to sports:
1) When you just start playing again after developing your body for awhile, your muscles have poor muscle memory, so it takes awhile to train the muscle you put on. When I came back from off-season this year, I couldn't serve(tennis) for ****. After a little while, about three weeks, I developed my strokes again, and this time they were more powerful and had alot more on them(spin/ppsi).
2) When you put on muscle, you'll naturally have to condition it. As far as golf goes, that means hitting the driving range for 30 minutes each day, for muscle memory.
All in all, muscle is good for any sport, as long as it doesn't hamper speed. I have to watch how big I get, because every lb I gain, is one more lb that I'll have to be dragging around the tennis court late in the 5th set of a ball-busting match. For sports, make sure you know what muscle groups you'll be utilizing most, and train those(accessory work if necessary). As Throttle and others said though, for any sort of physical activity, developing a foundation of strength in your legs, core, back, and chest couldn't hurt anybody.
