The big striker spent six months at Aston Villa in 2014.
The 35-year-old striker spent half-a-season playing alongside the England midfielder at Villa Park, during a six-month loan from Wigan Athletic in 2014.
Delph - now with Manchester City - emerged as a fine player in his last two seasons with Aston Villa, and Holt said he was the most impressive player he saw in the West Midlands.
The 26-year-old has gone on to bigger and better things inevitably, joining City in an £8 million deal last summer.
Christian Benteke - one of Holt's rivals during his time at Aston Villa - also left the Villans last summer and suffice to say their absence was felt last season.
Villa finished rock bottom of the Premier League table with a club-record low of just 17 points, with manager Remi Garde - who only replaced Tim Sherwood in November - sacked in Aprill.
But things seem a little more promising these days, with Roberto Di Matteo charged with the task of getting the club back into the Premier League under the reign of Tony Xia, who completed his takeover of the club a little earlier this summer.