The former Everton man has left the club as part of an ongoing refresh of key positions on and off the pitch.
It is understood he did not depart as a result of any disagreement or fall-out behind the scenes.
But the club identified areas where they needed fresh energy, direction and ideas which they felt he could not provide.
Tony Bloom used the word “refresh” in the official announcement of Weir’s departure.
Albion are renowned as a well-run club so any news of off-field changes or what looks like upheaval inevitably attracts attention.
Obvious assumptions at today's news were that either Weir had found a job at another club or there had been a major problem behind the scenes.
The Argus understands neither are true.
It is more a result of Bloom and his senior colleagues seeking to remain ahead of the field and punch above their weight.
Weir is regarded as a hard-worker and a respected figure who has done a good job in several areas of the club and it appears the decision to move on from him was not taken lightly.
While there has been no criticism of transfers or loans, either in or out, The Argus understands it was felt there was a need for new energy, new ideas and innovation.
The decision which surprised fans as it broke on Friday morning stemmed from a wish to keep looking forward as huge clubs in the world’s most competitive sporting league continue to snap at their heels.
Bloom and colleagues regard the way to do that is to challenge conventional thinking and, crucially, to make difficult decisions and make them early.
That appears to be what has happened with Weir.
There are other key appointments being made away from the pitch, including that of IT expert Mark Loch, who previously worked for British Airways, Tesco and the FA among other organisations.
His work so far includes new communication systems for Fabian Hurzeler and players and, for off-field staff, between the club’s bases at the Amex and Lancing.
Loch posted on LinkedIn: "I'm proud to have joined such a progressive and admired Premier League club and am excited about leveraging leading edge technology to advance us even further across all aspects of the club."
More changes and appointments will follow.
But the departure of a technical director and well-known former player will clearly be the most high-profile.