Defender Jason Kerr and Northern Ireland international Ali McCann have left St Johnstone.
Kerr, who started his career at the Perth club seven years ago, has joined Wigan in a deal worth around £600,000.
The 24-year-old captained the Scottish Premiership club to a historic League Cup and Scottish Cup double last season but has put pen to paper on a three-year deal at the League One side.
Saints chairman, Steve Brown, said: "During this transfer window, we have rejected bids for Jason, but Wigan Athletic met our valuation. From a club and, in particular, a financial point of view, it was an offer we could not turn down."
McCann, 21, has also left McDiarmid Park after joined Preston in a £1.2m deal - a figure that could rise above £1.75m with add-ons.
The midfielder - who is currently on international duty with Northern Ireland - has agreed a four-year deal at the Lilywhites.
He said: "It's brilliant, it's been such a long day today. I'm just so buzzing to get it all sorted and get it over the line and I just can't wait to get back and get in with the lads next week.
"St Johnstone are a great club. I've been there since I was young so it was difficult leaving because they've done so much for me when I've been growing up, but an opportunity to move down to a club like this is just too much to pass up and I just can't wait to get started."
Dendoncker and MacPherson joins Saints
St Johnstone did add to their squad on deadline day after signing Brighton defender Lars Dendoncker on a season-long loan.
The 20-year-old Belgian youth international said: "This is a fantastic opportunity for me.
"Having won both domestic cups last season, I'm joining St Johnstone on the back of an incredible achievement and I want to go there and create more happy times."
Midfielder Cammy MacPherson also joined the club on loan until the end of the season from St Mirren - who have the option to recall the player in January.