He signed for just £100,000 a year ago and just after eight appearances for the Blades his season was over after a bad injury against Rotherham United occured.
The Glasgow born striker will join Carl Asaba and Steve Yates in training before reporting to rest of the squad on 7th July.
"The players who missed chunks of last season will be doing a bit of running and weights work to help us catch up.
"I feel fine but it will be easier to measure my progress when the rest of the lads are back with me," he added.