Depends on how you look at it. If we keep him, he scores 10 more goals from January to the end of the season, and we get in the play-offs - I'd take the hit of losing him for free in the summer I think.
The situation with Vokes was totally different. He was at the very end of his Wolves contract, and after being out on loan for 3 seasons or so he managed 8 goals in 42 appearances. His value is a bargain now because Burnley took a punt on it, and it was a big punt and both they and the player...