The Scotland international previously turned down the offer of a new 12-month contract describing it as "derisory", but with the Portuguese giants deciding not to peruse their interest he may now perform a u-turn.
The 22-year-old finally made the break into regular first team contention last season making 17 appearances, memorably scoring in the 2-0 win over Middlesbrough, and forming a useful looking partnership with Jonathan Woodgate, but was unhappy with both the length and amount of his contract offer.
However Sir Bobby is still keen for Caldwell to sign-up and the player has now admitted that he may decide to stay at the club, and with Sunderland rumoured to be interested who could blame him.
Meanwhile one press report suggests that a swap deal to bring Michael Bridges to St James’ Park is still on, but with Clarence Acuna now the player offered to Leeds United rather than Nikos Dabizas.