The striker, named Clydesdale Bank Premier League Player of the Month for December, has moved to Sheffield United.
Having scored 11 goals for Stuart McCall's Well in all competitions in the first half of the 2012/13 campaign, Murphy will be badly missed.
But defender Ramsden is confident the Steelmen can secure second spot in the SPL table, and a place in the Europa League, without the hitman.
The former Bradford player said: "Jamie will definitely be a big miss for us.
"He is an excellent player and I am sure he will do well for Sheffield.
"Hopefully, though, he will be the last of our players to leave the club during this transfer window.
"If we can keep our squad together I am sure we can kick on in the second half of the season.
"We have to aim for second spot. If we can achieve that and get back into Europe next season, our season will have been a success.
"We have been pleased with how we have played in the first half of the campaign.
"We have had good spells and bad spells, but we know that, on our day, we are capable of beating any team in this division, home or away."
Ramsden, who has been dogged by injuries since signing a one-year deal with Motherwell in the summer, was annoyed the winter break came when it did.
The 31-year-old had forced his way into the Well first team.
He said: "I was just getting back into things after returning from a spell out injured when the break came.
"It happened at the right time for the rest of the squad. The spell over Christmas and New Year was hectic.
"I am sure we will be fresh and raring to go when we return against St Johnstone at Fir Park this weekend.
"I had missed quite a bit through injury so I would perhaps have been happy to keep playing.
"I have been made to feel very welcome by everybody at the club. I like it at Motherwell a lot.
"I've enjoyed playing in the SPL as well.
"The football is of a far higher standard to what I had been used to in England.
"It was disappointing to head into the break on the back of a 1-0 defeat at Celtic. But we played well and can take confidence from our performance.
"We are back training and have maintained our fitness levels during the break.
"I know all of the boys are refreshed looking forward to getting back against St Johnstone on Sunday."