Horgan, 24, is the star turn for League of Ireland side Dundalk, who have made headlines this season for an unlikely run to the group stages of the Europa League.
Calls for the former Republic of Ireland Under-21 international to get a senior call-up have intensified and Horgan looks set to leave on a Bosman free transfer next summer.
Reports in Ireland said Ipswich had a scout at Dundalk’s 2-1 win over Cork City on Tuesday night, a game in which the skillful winger scored the winner.
"There were about about 100 scouts watching him, I can tell you that," said McCarthy. "Quite clearly when I get asked a question about him by you there are no secrets, are there?"