Pompey have emphatically rejected what is understood to be in the region ofÂ Â£250,000 plus add-ons for the striker.
However, the door remains ajar for an improved offer '“Â with the Blues privatelyÂ indicating a potential deal would be considered ifÂ the tabled feeÂ rose substantially.
As revealed at portsmouth.co.ukÂ on Friday, Coventry have targeted Chaplin to replace 28-goal striker Marc McNulty.
The Scot'sÂ move to Reading was officially announced on Saturday morning as he signedÂ a four-year deal for an undisclosed fee.
That subsequently sparked a bid from Pompey's League One rivals for Chaplin, who at the weekend netted an 84th-minute winner in Kenny Jackett's side's 2-1 victory over the Hawks.
Despite now into the final 12 months of his contract, the Blues are determined not to let the 21-year-old leave on the cheap.
That resolveÂ has been strengthened by the knowledgeÂ Coventry have banked around Â£1m from the sale of McNulty.
In addition, the recent Adam Webster windfall ensures that, in terms of finances,Â Pompey do not need to sell any of their prized assets.
And Jackett has admitted interest presently does not match their valuation.
He said: '˜There have been enquiriesÂ but nothing of a level we would consider. The bid is not even close (to our valuation).
'˜The centre-forward market is a market on its own '“ and the closer you get to the window that accelerates, whether you are buying or selling.
'˜You get enquiries all the time. Recruitment teams are always talking to each other, managers definitely are, coaches areÂ and,Â when you go away to the Football League Conference, chief executives are as well. There are people gathering information all the time '“ yet it's probably serious bids when you need to talk.'
Chaplin took his pre-season tally to three goals in two matches as he added to his Cork City double.
Once again he appeared in Jackett's second-half starting line-up, working in tandem with Oli Hawkins against the Hawks.
Regardless, the Worthing youngster has grown tired of his lack of Fratton first-team action and is desperate for regular football.
In the meantimeÂ Jackett is eager toÂ strengthen, with the temptation of cashing in on Chaplin to bolster the hunt for an attacking replacement.