Tidser came through the Celtic youth team with Forrest and is now in his second spell at Morton.
Ahead of the two sides’ Scottish Cup quarter-final tie at Celtic Park on Saturday afternoon, the 28-year-old former Rotherham United midfielder has given his opinion on the 26-year-old winger.
Tidser told The Scottish Sun about Forrest: “There are still Celtic fans out there who don’t seem 100 per cent sure of Jamesie. I don’t understand that at all and for me, it’s a shame.”
Forrest has been at Celtic his entire professional club football career so far and is one of the most important players in the current Brendan Rodgers’s team.
The 26-year-old winger has won the league title with Celtic six times, and the Scottish Cup and the Scottish League Cup thrice each.
Forrest may be under-rated, but no one can deny his importance to the Hoops, who are a better team with him in it.