Championship strugglers Millwall have signed Reading defender Shaun Cummings in an undisclosed deal.
The 25-year-old, who has featured seven times for the Royals this season, has agreed a two-and-a-half-year contract.
"He can play at wing-back or at right-back and he can run all day long," Lions boss Ian Holloway said.
"I think he can be a real asset for us over the short and long-term. He gives us a new option and as a player he can contribute in defence and in attack."
Former Chelsea trainee Cummings joined Reading in 2009 and made a total of 86 appearances for the Berkshire club.
He becomes Millwall's fourth signing of the January transfer window, following the additions of Paris Cowan-Hall, Dan Harding and Stefan Maierhofer.
|Millwall's January business so far|
|Paris Cowan-Hall (Wycombe, undisclosed)||Scott Malone (Cardiff, undisclosed)|
|Dan Harding (Nottm Forest, loan)||Josh Wright (Leyton Orient, free)|
|Stefan Maierhofer (Unattached, free)||Paul Robinson (Portsmouth, free)|
|Shaun Cummings (Reading, undisclosed)||Jermaine Easter (Bristol Rovers, free)|
Holloway told BBC London 94.9 he was planning to strengthen his squad further in a bid to avoid relegation from the Championship.
The Lions have only won one of their last 11 league games and are currently in 22nd place, two points below Leeds.
"I am going to endeavour to get a bit more confidence in the group by bringing some other players in to help them," he said.
"We have got to turn this around in the league. I believe some changes will help that because confidence seems to be draining away from people."
After seeing his side lose 1-0 to bottom of the table Blackpool on Saturday, Holloway stressed the importance of unity as the club battle the drop.
"What it is about is staying composed and as a group," the 51-year-old said. "There are an awful lot of games left and 63 points to play for yet.
"I have got to make sure that I don't panic and neither do the team and we keep going.
"This club's motto is 'stronger together'. Sometimes when things get bad you get a siege mentality. I have got to make sure I bring the right balance."