Mackay was a bit-part player for the next two seasons and provided some useful goals including winners against Oldham and Huddersfield, but he did not manage to force his way into the starting eleven on a regular basis. Most of his first team football in 2009/10 was during a six month loan deal at Gateshead, with his time in a Pools shirt restricted to a solitary sub appearance at Southampton. He fared little better in his next season, managing just one start and two more appearances from the bench.
Mackay was a regular and successful player with the reserves throughout his time at the club. He managed 45 goals in his 69 appearances for the second string but, with first team chances likely to remain scarce, he was unsurprisingly released in May 2011.