Michael Hector has committed his future to Reading after signing a new three-year contract with the Championship club.
Watford have confirmed the signing of Austria defender Sebastian Prodl from Werder Bremen.
Gary Harkins has rejoined Dundee from SPL rivals Kilmarnock for an undisclosed fee.
The midfielder had fallen out of favour at Rugby Park and had not played since a 1-1 draw with Hibernian on December 23.
The 28-year-old spent two seasons at Dens Park before joining Kilmarnock in June 2011.
Despite the threat of relegation for the SPL's bottom side, Dundee boss Barry Smith earlier argued Dundee were still a "great club to play football for".
He said: "The bonus is that we are in the SPL.
"I think players should want to come here to a club that is run properly now, given all the problems we have had in the past.
"It is a tight ship now, we are living within our means and that is the way forward for us.
"We want to bring guys in who are hungry to do well here and to make sure that we stay in this league, players who bring in quality but who also have that fight and desire to do well for Dundee."
Meanwhile, Smith believes Kilmarnock players will put aside any fears for their future when they travel to Dens Park.
It was revealed during the week that the Ayrshire club reached agreement with a creditor over an unpaid sum of £16,000 to avoid the threat of a winding-up order.
Financial fears resonate with Smith, who has come through turbulent times himself at Dundee, experiencing administration as a player in 2003 and replacing Gordon Chisholm as boss when the club were plunged into administration again in October 2010.
The former Celtic defender believes the match will allow Killie players to forget any concerns they may be harbouring.
He said: "It is a bit unnerving when you see that things aren't getting paid. Obviously their thoughts might be elsewhere.
"I know that players tend to focus just on the football but things off the park can affect the way they are thinking going into the game.
"But what tends to happen is that when you go on to the park you forget about everything else and you concentrate fully on the game. It is a release."