The afternoon didn’t go as planned, but it shouldn’t take away from a monumental achievement. He joins a list of only other 14 Owls players to have achieved the feat.
The first of those 400 appearances came as Palmer made his Wednesday debut in midfield, in an August 2010 League Cup match against Bury.
The Owls won 1-0 thanks to a Giles Coke winner - but who else played in the match - and which two future Wednesday players featured for the opposition?
Here’s a run through memory lane.
13. James O’Connor
Left Wednesday in 2011 to go Stateside, first as a player with Orlando City before going into coaching. Managed in the MLS but has since ‘gone upstairs’ as technical director with USL side Louisville City. On as a sub. | Getty Images
14. Clinton Morrison
A forward of some repute, arriving at S6 later in his career with World Cup appearances with the Republic of Ireland, Morrison left in 2012 and played for Colchester and Exeter before finishing up in non-league. Now a prominent pundit on Sky Sports and a regular at Owls matches. | Getty Images
15. Tom Lees
In the opposition for Palmer’s debut while on loan from Leeds, Lees is a former Owls captain of over 250 appearances. Left in 2021 to sign for Huddersfield, where he remains. | Getty Images
16. Ryan Lowe
A Bury legend, Lowe would go on to sign for the Owls the following season and help achieve promotion from the third tier. Like a few on this list, he left to sign for MK Dons and played for others including Tranmere, Crewe and Bury twice over before going into management. Now at PNE. | Getty Images