The phrase "almost irreplaceable" is correct and usable in written English.
It can be used to describe something or someone that is very valuable or unique, but not entirely impossible to replace.
Example: "The team's lead designer has been with us for over a decade and has become almost irreplaceable in her role."
Alternatives: "nearly indispensable" or "virtually unique".
Suggs seemed almost irreplaceable.
A one-off, almost irreplaceable concept car has been let loose on the public road by the man who built it.
But Rondo is almost irreplaceable, given his confidence and comfort at the position, his role as a team leader and his singular style and game.
When host Simon Amstell left Never Mind the Buzzcocks to kickstart his stand-up career and write new sitcom Grandma's House, many fans of the show felt Amstell's catty wit would be almost irreplaceable.
Each Long Islander thus lost is "almost irreplaceable," Mr. Crosson said, in an economy where local corporate recruiters have been struggling for years to find enough college grads to fill all their job openings.
There are those, not least Lawrence Dallaglio, who view Launchbury as the modern equivalent of the former Saracens and England flanker Richard Hill, whose unfussy, down-to-earth excellence in the game's less glamorous areas made him almost irreplaceable.
"He's almost an irreplaceable guy," said Syracuse's men's basketball coach, Jim Boeheim, who has worked with Tranghese for Tranghese's entire tenure.
Graham Norton (R2) The proof, if it were needed, that (almost) no one is irreplaceable.
Since respiration is irreplaceable in almost all living creatures, mutations occurred within respiratory chain complexes can lead to various severe physiological defects directly or indirectly.
For example, every gene in a pathway that instigates DNA copying was irreplaceable, but almost all the genes in the molecular pathway that in humans manufactures cholesterol could be swapped.
Earlier this month, news stations across the country lined up tell the story of the discovery of irreplaceable treasures almost marked for the trash heap.
