Powell, who spent last season on loan at Wigan, is expected to once again move on a temporary basis until the end of the current campaign.
However, the deal being discussed for Lawrence is thought to be a permanent one.
Highly-rated attacking prospect Powell moved to Old Trafford from Crewe in 2010 and has gone on to make seven appearances for United.
The 20-year-old made 41 appearances during his loan spell with Wigan, scoring on 12 occasions.
Forward Lawrence was handed his first-team debut for United by interim manager Ryan Giggs at the end of last season in the 3-1 win over Hull City.