Diaby has recently been released by Arsenal, but had not started a Premier League game for the club since 2013.
An injury sustained against Sunderland at the end of his first season at the club was a huge setback, from which he never really recovered, showing flashes of form inconsistently.
It was however just in August and September 2012 that he led Arsenal to an impressive Premier League win over Liverpool at Anfield with a dominant display, and scored a winner for France in a World Cup qualifying match.
Arsene Wenger was a huge fan, and even early last season he was quoted by ESPN discussing his plans to convert Diaby's box-to-box style to become a defensive midfielder, a position eventually taken by the younger and healthier Francis Coquelin.
Diaby, 29, was never going to get the regular football he needed to reinvent himself at Arsenal, but at West Brom there is a spot available as a replacement for Youssuf Mulumbu.
The Baggies are wise to take their time assessing the injury-prone star, and a pay-as-you-play deal is one possibility.
The prospect of Diaby taking a medical provoked discussion among fans, while for others it was an opportunity to crack jokes at club and player's expense.
Here is a look at how Twitter reacted...
Oh no, why make Abou Diaby have a medical? Hasn't the poor boy suffered enough? #wbafc— Gwynfryn Hughes (@Gwyn82) July 23, 2015
If we sign diaby, it HAS to be on a pay as you play deal, can't fork out £££££££ p/w if he is only going make about 6 appearances! #wbafc— josh hynd (@josh_hynd) July 23, 2015
SPOTTED: Abou Diaby arriving at West Brom for contract talks... pic.twitter.com/xsb3i0YkDw— BreatheSport (@BreatheSport) July 23, 2015
Abou Diaby in talks with West Brom. Signing could take place this week, with medical due to be completed in 2019.— James Martin (@Pundamentalism) July 23, 2015