The 28-year-old has been on trial with PNE for three weeks but only got his first taste of match action in the reserves on Tuesday.
He played 90 minutes of the Central League clash with Walsall, looking lively in the first half before fading during the second period.
Wickham missed a penalty early in the game but showed flashes of what he is all about, linking up well with Josh Murphy up front.
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It might be that North End give the former Crystal Palace man longer to work on his sharpness, with needing him to be able to make an impact later in matches.
They have been impressed with his ability and approach but match fitness was always going to take time.
His last first-team start was in July 2020 when on loan at Sheffield Wednesday from Palace.
As a free agent, Wickham can join a club outside of the transfer window parameters.
Were PNE to decide to sign him at some point, it would be a decent level of football for Wickham to come into.
His strength up front is an attraction and he would suit Frankie McAvoy’s liking for playing two up front – he would be a good foil for a more nimble striker.
That said, Wickham showed a good turn of pace himself a couple of times during the reserve game.
Hereford-born Wickham started his career with Ipswich, scoring 15 goals in their colours which earned him an £8m move to Sunderland in their Premier League days.
He had spells on loan at Wednesday and Leeds in his Sunderland days before Palace signed him for £9m. A damaged cruciate ligament in his knee kept him out of first-team action for the best part of two years and in January 2020, he returned to Wednesday on loan.
That loan spell was broken in two by the pandemic which saw football halted for more than three months.
North End have left a space free in the squad they have registered with the EFL to cover the possible addition of Wickham later on.
Up to 25 senior and loan players can be registered by Championship clubs.