Former Bury defender Knill was impressed with O'Brien during his recent loan stint at Sheffield Wednesday and is hopeful that Bolton will allow the Republic of Ireland U21 international to make the temporary move to Millmoor.
O'Brien was in the Bolton squad for their game with Manchester City on Monday night and is very highly rated by Trotters manager Sam Allardyce. Whether the Wanderers boss wants to loan out the youngster for a second time remains to be seen.