The Baggies worked until the wire to recruit Crystal Palace attacking midfielder Hindolo Mustapha on a deal until the end of the season.
The 19-year-old follows his fellow Eagles colleague Danny Imray, who checked in on loan last week, to The Hawthorns.
Mustapha joined fellow teenage attacker Jamaldeen Jimoh-Aloba through the doors as the Villa prospect, 19, returned to his boyhood club on a loan deal two-and-a-half years after Villa snapped him up from the Baggies' academy for a reported £1million as a 16-year-old.
Selhurst Park youngster Mustapha is yet to make his senior debut in club football, but the London-born attacking midfielder has three caps for Sierra Leone.
Jimoh-Aloba has made five senior appearances for Villa. He scored his first senior goal in last week's Europa League win over RB Salzburg.
Jamaldeen Jimoh-Aloba, who Villa signed for £1million from the Baggies three years ago, returned on loan. (Photo by Adam Fradgley/West Bromwich Albion FC via Getty Images)
Jamaldeen Jimoh-Aloba, who Villa signed for £1million from the Baggies three years ago, returned on loan. (Photo by Adam Fradgley/West Bromwich Albion FC via Getty Images)
EDITORIAL USE ONLY. No use with unauthorized audio, video, data, fixture lists, club/league logos or 'live' services. Online in-match use limited to 120 images, no video emulation. No use in betting, games or single club/league/player publications
Eric Ramsay was unable to add any experience on deadline day. (Photo by Adam Fradgley/West Bromwich Albion FC via Getty Images)
The two youthful additions were the only business Albion managed in a sign of the scale of the task on the hands of head coach Eric Ramsay as he looks to arrest deep Championship relegation fears. The pair make it four additions this month after Max O'Leary and Imray.
There were departures from The Hawthorns, as goalkeeper Joe Wildsmith was sent to Championship high-flyers Middlesbrough on a loan deal until the end of the season, where he will go in as a back-up.
Winger Samuel Iling-Junior saw a difficult loan spell at Albion from Villa cut short as the 22-year-old was recalled by his parent club and sent on loan to Italian top flight outfit Pisa.
One of the biggest developments of the day for the Baggies was the club are progressing in their hunt for a new technical director, with Dominic Price, who occupies the same role for Israel champions Maccabi Tel Aviv, poised to move to The Hawthorns.
Goalkeeper Joe Wildsmith moves to Middlesbrough on loan. (Photo by Adam Fradgley/West Bromwich Albion FC via Getty Images)
Goalkeeper Joe Wildsmith moves to Middlesbrough on loan. (Photo by Adam Fradgley/West Bromwich Albion FC via Getty Images)
The club are set to confirm the reported exit of club president and sporting director Andrew Nestor, a long-term associate of owner and chairman Shilen Patel, after the former was dismissed following a series of failed decisions.
Albion turned their attention to attack-minded midfield players following last week's hamstring injury to Karlan Grant, which will sideline the regular for three months.
The Baggies explored a potential deal for Jimoh-Aloba - who came through the youth ranks between the ages of six to 16 before his departure - and completed a loan deal ahead of interest elsewhere.
Championship rivals Preston were competing for the teen's signature.
Young defender Michael Parker, 21, left for Swedish side Örgryte IS in a permanent deal having never made a first-team appearance. Prospects Harry Whitwell and Ollie Bostock, who both had loan interest, did not depart.