If he were to leave the club after say one year then the expenses will at most have been £10m + £6.24m (52 x £120,000) equating to a total sum of £16.24m.
Now if we're being realistic, say he was a flop then I can't see him leaving for a fee as paltry as £16m and we would be expecting between £20-30m at least.
So based on those figures (it may be more) we'd be looking at a profit of between £4-14m from it, and if wages were an issue they could be subsided from that.
Therefore, we'd either be still in profit, back to square one or making a small loss (worse case scenario), which is a fair gamble for me considering our stature.
Or he could be a fairly decent to great signing where we'd be even better off.