Celtic are closing in on the signing of Ryan Christie and Dinamo Zagreb defender Jozo Simunovic.
Inverness have given the Scotland Under-21 international permission to speak to the Scottish champions who, Press Association Sport understands, have agreed a fee for the Croatian centre-back Simunovic with discussions continuing.
Simunovic, 21, has eight caps for Croatia's Under-21 side and could be regarded as a replacement for Dutch defender Virgil van Dijk, who has been heavily linked with Southampton with the fee reported to be as much as £11million.
However, no deal has been agreed yet with the Barclays Premier League club.
Celtic had an initial bid for Christie, 20, rejected on Friday but now look set to conclude a deal before Tuesday's transfer deadline.
An Inverness statement read: ''As a result of a further approach from Celtic FC, and following discussions with the management team and the player, the board of Inverness Caledonian Thistle FC can confirm that Ryan Christie has been given leave to travel to Glasgow to discuss personal terms.''
Celtic signed Manchester United left-back Tyler Blackett on loan on Saturday. The 21-year-old Old Trafford player can also play at centre-back.
Christie is more likely to be one for the future with Inverness boss John Hughes confirming on Saturday that he hoped Celtic would loan the attacking midfielder back to Caley Thistle for the rest of the season, if a deal went through.
Christie, whose father Charlie played for both Celtic and Inverness, won the Scottish Football Writers' young player of the year award and starred as Caley Thistle beat Ronny Deila's men in the William Hill Scottish Cup semi-finals last season.
Christie has scored nine goals in 66 first-team appearances, including two this season, and can play wide midfield as well as just off the striker.