However there is positive news ahead of Sunday as full-back Daniel Evans returns from suspension and is joined by wing Tom Prydie, who returns from an ankle injury.
Crucially Jason Tovey is also back at ten following a spell on the sidelines while there is only one change upfront, with Hugh Gustafson stepping in as hooker.
Second-row Coombs is another returnee after international duty and he insists it is imperative they keep their home form ticking over following a loss to Ulster on their travels last time out.
"We can't let things slip now," he said. "We had a very good start to the season and it's important to get back to that form and start winning games again.
"Beating Glasgow was a massive and now we have to take another step and get the win against Connacht, who have got their game going and have won their last three.
"They've scored a few off the driving lineout and they have a good scrum. We've been working hard and need to counteract that to give our backs the ball they need to play. I'd like to think we have enough up front to hold them out."
Connacht are a team on an upwards trajectory with three wins on the bounce in the RaboDirect PRO12 - yet they will have to defy history to make it four.
Not since the 2002/03 season have Connacht strung together that many wins in the competition, but they are unbeaten against the Dragons in four of their last five match-ups.
Should Pat Lam's men accomplish the defeat, they will do so with an unchanged starting XV from their last victory against Benetton Treviso.
Robbie Henshaw slots straight back in from Ireland camp at No.15, while skipper John Muldoon continues to partner Eoghan Masterson - starting for the fourth time this season - in the second row.
Prop Ronan Loughney is on the bench after recovering from injury and Lam is eager to keep the momentum rolling as he eyes further progression up the table.
"It's been a while since our last outing but we're in good shape after training hard during the break," he said.
"Coming off the back of three straight wins gives us confidence but we're very much aware that we haven't won four in a row in quite some time.
"We also have to look at the threat of the Dragons who are a strong outfit at Rodney Parade. They've only been narrowly beaten by Leinster and Munster at home.
"If you look at all the games they play there, their line speed is faster, their contact is faster. The crowd are also a very passionate bunch which is another challenge for visitors.
"But we know what we need to do. We've targeted this next block of games and everything is about the process we go through as a team to earn the wins and valuable points to move up the table."
Sunday 23rd March
At Rodney Parade, 3.05pm.
Referee: George Clancy (IRFU, 60th competition game)
Assistant Referees: Neil Hennessy, Simon Rees (both WRU)
Citing Commissioner: Aurwel Morgan (WRU)
TMO: Gareth Simmonds (WRU)
Live on BBC Wales.