The early front-runners in the Championship - after back-to-back wins over Reading and Barnsley - Bullen is boosted by the return to fitness of midfielder Barry Bannan, plus the availability of goalkeeper Keiren Westwood and defender Dominic Iorfa following suspensions.
A calf problem ruled Bannan out of the 2-0 win over Barnsley last weekend, but the Scot trained today and travelled with the squad down to London this afternoon.
“He’s got a big chance of playing this weekend, he’s available for selection so we’ll assess his training session this morning,” said Bullen.
“It’s the first one he’s joined in on this morning and he’s spent all week with the sports scientists and fitness guys, so we’ll make a decision on that one, whether he starts or is in the squad.
“It’s a nice headache and there’s even more pressure on picking, never mind an 11, but 18. He’s certainly come back into the reckoning for a tough game down at Millwall.”