Kenny Jackett revealed Pompey did not offer a deal to Victor Adeboyejo because his current squad is already loaded with enough forwards.
The Nigerian signed for Championship outfit Barnsley on a three-year deal last week, after being monitored by the Blues.
Adeboyejo, 19, trained with Pompey at their Roko training base last month.
Jackett also analysed the former Leyton Orient player’s performances after he featured in two trial matches for Chelsea under-23s against Swansea and West Ham respectively.
The Pompey manager admitted he did speak to the forward but did not pursue a deal because he has enough attackers at Fratton Park.
‘We did talk to him and we did discuss a deal at different times,’ said Jackett.
‘But he is not somebody who we put a bid in for.
‘We felt in terms of the forward positions that we already have a high amount of players.
‘Right now wasn’t the right time for us.’
The Blues have also been linked with a move to Bruno Andrade.
The Boreham Wood attacker is currently the National League’s joint-top scorer, along with ex-Pompey striker Ryan Bird, having netted nine goals to date this season.
Andrade, 24, played a full game in the Wood’s 2-1 FA Cup first-round victory against Blackpool on Saturday.
The Portuguese talent has also trained with the Blues and was in the Westleigh Park stands for the reserves’ 2-1 Premier League Cup defeat to Everton.
Boreham Wood chairman, Danny Hunter, insisted they had not received a bid for Andrade. Jackett confirmed Pompey have yet to make an offer for the former QPR forward but will continue to monitor the player’s progress.
The Blues boss has also cast his eye over Mohamed Maouche, Thomas Juel-Neilsen and Ceykan Karagozlu since taking charge in June.