The striker signed a pre-contract deal at the Liberty Stadium this week following talks over a move when his contract ends.
The deal – rumoured to be at around £300k per year – was too much though for Motherwell as McGhee told BBC Sport "We tried to sign Stephen Dobbie, but he went to Swansea for money we couldn't afford."
Dobbie has scored 47 goals in 83 appearances for Queen of the South and will make his final appearance for the club tomorrow against Livingston before his move to South Wales.
The signing was an extra boot for Martinez when it was also revealed that Championship rivals QPR and Ipswich were also interested in gaining his signature.
This article first appeared on JACKARMY.net.