Not a prob.

Let me also clarify that through my own experience (I have been known to break out in a 10+ mile run) that so long as the vast majority of your training is of the muscle building sort, your body doesn't just unadapt because of one or two workouts. Keep that in mind. However, if you are clearly dominating your workout time with cardio work, you are going to have a damn hard time putting on weight and muscle. Likewise, anyone that does a lot of cardio (women) are not likely to build masculine bodies by hitting the weights... even if their test levels were equal to a man's.

So you won't see a world class marathon runner being built like a bodybuilder regardless of their dedication in the weight room, and you won't see a bodybuilder look like a marathon runner just because they do a little running. But the more you mix and match, the less likely you are to be great at either running or bodybuilding.