Eric in Chicago

Just back from the track with the new S2 club racer. Car ran like a champ all weekend. The last session I had a problem getting the car into 3rd gear. got off line and tried 2nd, would not engage, 3rd,4th and 5 were all good. Pulled into the paddock and let the car cool down. Tested the gear engagement and it would go into 1st with a fair amount of resistance, second was easier 3rd-5th were no problem. Shifting was done with the engine running and while stopped. With the engine running, clutch pressed in, reverse was difficult to engage and the car seemed to jump a little when engaged (clutch still in) The box was opened last month when the LSD was installed and everything was in great shape. 3 track days and now this. Yes I heel toe, matching revs etc. Did have a fellow instructor drive the car and got hung up on my large gas pedal (bird industries) which saw the car hit some pretty high revs, but that should have nothing to do with the clutch/gear box issue.
I am hoping it is the clutch not the synchros.
Anyone have any ideas as to what the symptoms coud be pointing to??I read all the archives and could not find anything close to an answer)

PorscheDoc

Throw out bearing possibly?