The 30-year-old has made 21 appearances for Hearts this season but has not featured since the turn of the year and was allowed to move to Fir Park until the end of the campaign.
Gomis could now make his debut in Tuesday night’s match against Partick Thistle at Firhill.
The former Cowdenbeath, Dundee United and Birmingham player said: “Yesterday after training, the manager Robbie Neilson called me in his office and told me Motherwell were keen to take me on loan until the end of the season.
“I was kind of surprised but anything can happen in football.
“I have one more year on my deal at Hearts but we will see what happens. I am just concentrating on playing and winning games.
“I don’t want to speak about Hearts anymore, I just want to focus on Motherwell. It’s always been a good team, they play attractive football, score a lot of goals and they are never easy to play against.
“I think we can achieve top six. It’s not going to be easy because there are a lot of teams around about us in the table. We just have to win games and see where it takes us. I am fit and ready to go.”
Wide midfielder Chris Cadden has impressed in his first two starts for the club following Liam Grimshaw’s exit but manager Mark McGhee felt more experienced cover was needed to help Keith Lasley and Stephen Pearson in central midfield.
“We have shown in a couple of games, certainly the Hearts game at Tynecastle when we lost by six, we were very short of central midfield players,” said McGhee ahead of talks with James McFadden about a potential extension to his short-term contract.
“We had to improvise and play Josh Law in the middle. That exposed us in terms of needing another experienced central midfield player and he is certainly that. You know exactly what you are going to get.”
Meanwhile, Craig Reid has left Motherwell after almost a year without a first-team appearance. The 29-year-old returned from a knee injury in the autumn and played seven games on loan for St Mirren.
THE SCOTSMAN ON SOCIAL MEDIA