Kelly, 32, enjoyed a sparkling Latics bow against Blackburn last night after his late January switch from The Hawthorns to the DW Stadium.
He was named broadcaster Sky's man of the match, but only after he hobbled off 15 minutes from time in a plucky goalless draw at Ewood Park.
Kelly, a September 2022 Albion free transfer, will undergo a scan on his knee this week after admitting in a post-match tweet he was 'a broken man' and 'devastated is an understatement'. New Latics boss Shaun Maloney conceded the injury does not look good.
Maloney told Wigan Today: "I thought he was brilliant, I thought he was very brave in possession, and out of possession as well.
Im a broken man, devastated is an understatement. The boys will build on a good performance thanks for the support and appreciation out there 🙏🏻 pic.twitter.com/rWQiFVtotD— Martin Kelly (@MartinKelly1990) February 6, 2023
"The challenge he made was a goal-saving, match-saving
"His injury doesn't look good, it doesn't look good at all.
"I hope that changes in the next few days, but I'm devastated for him.
"We brought him in as a leader off the pitch, as much as what he can bring on the pitch.
"He's been brilliant with us while he's been here, and we'll be keeping our fingers crossed."
Kelly's tweet read: "I'm a broken man, devastated is an understatement. The boys will build on a good performance thanks for the support and appreciation out there."
The former Liverpool and Crystal Palace defender and one-time England international made just seven appearances for Albion before being sent on loan.
He started four league games, most recently in the 2-0 home defeat to Bristol City under caretaker boss Richard Beale in mid-October.
Kelly, who signed a two-year deal until summer 2024, did however start in both of Albion's FA Cup third round ties against non-league Chesterfield.
Wishing you a speedy recovery, Martin. 💙🤍 https://t.co/8aERbUGlNM— West Bromwich Albion (@WBA) February 7, 2023
Bottom side Wigan's unlikely point in Blackburn was enough to keep Carlos Corberan's Albion in the Championship play-off positions. The Baggies remained sixth, clear of Rovers on goal difference.