He was referring to Michael McDowell, starting his first race in the 00 car for M. Waltrip. This was the Reuteman ride before who moved into the 44 car vacated by D. Jarrett.
The comment was in regard to how near the end of the race McDowell held Burton up after Hamlin got by him. Burton is claiming it may have cost him the race. McDowell should have moved over once he was lapped by Hamlin, since the race was near the end. It is the expected procedure.
McDowell up to that point was getting high praise for his first race, staying on the lead lap almost the whole race and finishing in 25th.