Maybe it's settling into a rhythm that's his problem. Look at his play time since joining Chelsea - lines in bold are when he's come on as the 80th minute sub, or not been used at all. Latest game on top.
H- Brentford - Started; full game
H- Wigan - Unused Substitute
A- Newcastle - Started; Off 42 min
A- Reading - On 90 mins
A- Brentford - On 81 mins; assists a goal
A- Swansea - Started; full game
H- Arsenal - On 80 mins
H- Southampton - Started; full game; scores once
A- Stoke - Started; Off 70 min
H- Swansea - On 80 mins
A- Southampton - Started; full game; scores twice
He's ineligible to play for Chelsea in the Europa League. So this is the above in words:
- Starts and plays 90 mins, scores
- Sits on the bench for 80 minutes in the next game
- Starts and plays 90 mins, scores
- Back to the bench for 80 mins you go!
- Ooh, the bench again for 81 mins; gets an assist
- Ha! How's that? 90 mins on the bench for you now... how dare you get an assist in the last game
- Okay, let's put you back against your old team... ah 42 mins later comes off with a bloodied nose (should've had a penalty)
- All right, that wasn't too bad. Back on the bench for you.. oh shit, I forgot you were there.
- Here you go, another start. Get a goal or you're benched in the next game. Actually, fuck that, you're benched the next game anyway.