Centre Evans joins the exclusive 100 Club as Blues look to maintain their unbeaten start in Europe this season.
Director of Rugby Mark Hammett makes just one change to the side that defeated Irish 24-14 at BT Sport Cardiff Arms Park last weekend.
Wales international Sam Warburton makes a return to the starting line-up and takes the number seven jersey for the game in Reading.
Hammett said: “We’re looking forward to the return game with London Irish and building on what we achieved last weekend.
“It’s fantastic to be top of Pool 1 after three games but we’ve achieved nothing yet and have three hard games to contend with before we can even think about the possibility of knock out rugby
“We still haven’t put together an 80 minute performance, which we are working so hard to do. That’s our challenge and we need that consistency going forward.
On the return of inspirational back row Warburton, Hammett added: “Sam had a great pre-season and it doesn’t matter who you are or how good you are, it takes time on the field to get right back into it.
“Early on this season he was getting back into the rhythm of the game. But during the Test series for Wales we all saw he was back on top of his game. We’re now looking forward to seeing him back out in a Cardiff Blues jersey.”
Cardiff Blues: 15 Adam Thomas, 14 Alex Cuthbert, 13 Cory Allen, 12 Gavin Evans, 11 Richard Smith, 10 Gareth Anscombe, 9 Lloyd Williams; 1 Gethin Jenkins, 2 Matthew Rees (c), 3 Adam Jones, 4 Filo Paulo, 5 Josh Turnbull, 6 Macauley Cook, 7 Sam Warburton, 8 Josh Navidi
Replacements: 16 Kristian Dacey, 17 Sam Hobbs, 18 Craig Mitchell, 20 Ellis Jenkins, 20 Manoa Vosawai, 21 Lewis Jones, 22 Gareth Davies, 23 Dan Fish