The former West Brom man will move subject to international clearance and remain with the Championship club until the start of the MLS campaign in mid-February.
"As soon as we found out Liam was a possibility, we moved quickly," manager Malky Mackay told Wigan's official website.
"We have him until the start of the MLS season in mid-February and hopefully we can make good use of his experience in that time."
Elsewhere, Kazenga LuaLua has signed a new deal that will keep him at Brighton and Hove Albion until 2018, while Chelsea have loaned out youngsters Todd Kane and Lewis Baker to Championship duo Nottingham Forest and Sheffield Wednesday respectively.
Kane spent the first half of the season on loan at League One side Bristol City, but was recalled by the Premier League leaders on Wednesday.
The 21-year-old full-back has subsequently moved to the City Ground on a temporary basis until the end of the season.
Midfielder Baker, 19, has also opted to go in search of experience in the Championship after agreeing to a youth loan at Wednesday that could potentially run until the end of the campaign.
Baker has caught the eye with his progression through Chelsea's youth teams and made his first-team debut as a substitute in a 2-0 FA Cup win over Derby County in January 2014.
Championship strugglers Blackpool have landed Tottenham centre-back Grant Hall on loan.
Hall has recently returned from a spell at Birmingham City, for whom he made nine appearances.
Leicester City's Jack Barmby has moved to Rotherham United on loan, while Ipswich Town have completed the signing of free agent Noel Hunt following his release by Leeds United on Wednesday.
At Molineux, Kortney Hause has penned a new three-and-a-half year deal with Wolves until 2018.
The defender follows team-mates Ethan Ebanks-Landell and Dominic Iorfa in committing his future to Wolves, the duo having signed new contracts earlier this week.
