When quizzed on what he had to do to secure a permanent Magpies berth Donaldson replied:
"Keep playing like I have been playing but to the team structures and hopefully it will be enough. It will be good to have players like Tiaan [Falcon] or Ihaia [West] outside me because they have a lot experience and knowledge. Tiaan is the same age so I will be able to communicate with him."
Magpies head coach Craig Philpott admitted it was tough for Donaldson to miss the club final.
"But Zac has put his hand up with some outstanding club footy and he deserves this opportunity."
Both he and Magpies centurion Chris Eaton have yet to be contracted but with Wilson injured and 2015 All Black Brad Weber not expected to be ready for action until round three in the Mitre 10 Cup, Donaldson and Eaton could share the load in the halfback role until then and the next fortnight could determine who gets the start when the Magpies open their campaign against Southland at Napier's McLean Park on August 19.
Former Hurricanes flanker Tony Lamborn didn't play much club rugby this season because of a back injury but Philpott said he has recovered and will start in the No 6 jersey today.
Two of the Magpies four new imports, Waratahs-bound lock Nick Palmer and former Hurricanes midfield back Cardiff Vaega, will start for the Saracens today.
After today's game the Magpies will play Manawatu in Palmerston North on Friday before having their pre-season camp in Dannevirke next weekend.
■ Saracens team: Hayden Hann, Ash Robinson, Cole Eru, Cardiff Vaega, Mason Emerson, Tiaan Facon, Zac Donaldson, Marino Mikaele-Tu'u, Fa'alemiga Selesele, Tony Lamborn, Ben Parsons, Nick Palmer, Pouri Rakete-Stones, Jacob Devery, Jason Long (c).
Substitutes, forwards: Teremoana Joel, Mark Braidwood, Mason Kean, Geoff Cridge, Ben Hamelink, Tyler Symon-Burke. Backs: Chris Eaton, Dan Snee, Kalin Paewai.