Donnelly banged his knee on the All Blacks tour in November last year and was invalided home.
Then, after what he described as a hard-working off-season, the lock landed awkwardly on his shoulder 10 minutes into his first Highlanders pre-season game and spent more than a month on the sidelines.
But he has slowly been getting back into work and will lock the scrum with Jarrad Hoeata when the Highlanders play the Brumbies in Invercargill tonight.
"It's just good to be able to get a start. I'm in a pretty competitive position so any time you get a start has to be a bonus," he said.
"Obviously, it wasn't an ideal way to start the season. I just partially dislocated my shoulder so I could still do all the training, running and everything, just could not do the contact.
"It was awesome seeing the guys start off so well and win those games, but at the same time you're injured and can't really help them."
Donnelly did get his first start of the campaign, only to run into the Crusaders juggernaut at Carisbrook.
"It wasn't too bad: made a few tackles, made a few mistakes, but it was only one game. We only had about three lineouts so it was pretty hard.
"This week is a massive game for us. They [the Brumbies] have not had the greatest of starts so they'll be throwing everything at us. But we've just got to stick to our game plan and make it hard for them as a forward pack."
Donnelly said the Highlanders needed to build on the promising start they had made in the competition, and that started against the Brumbies.
"We just need to play to our potential. That is the key this year. The culture we have created has really helped us - just a lot of fresh new guys coming in and obviously Jake [coach Jamie Joseph] has played down here and knows what it is about playing down here."
An All Black over the past two seasons, Donnelly met All Black coaches Wayne Smith and Steve Hansen this week but said there was not much to talk about, as he had not played much.
"It's a long year, plenty of rugby still to be played. At the end of the day you can only control what you can control."
Donnelly and the side will want to make a statement tonight for a game which looms pivotal in the season.
The Highlanders have exceeded expectations for the opening part of the season, but with that comes increased hope.
They need to pick up a win against a struggling Brumbies side, which is coming off the bye, after four straight losses.
The Brumbies have named Wallaby Adam Ashley-Cooper - who announced this week he is moving to the Waratahs next season - on the wing, while youngster Matt Toomua, who usually plays in the inside backs, starts at fullback.
Wallabies prop Salesi Ma'afu gets his first start for the season.
The match will be refereed by Stuart Dickinson, the third time this season the Highlanders have had the Australian whistle-blower in charge.
His rulings, or somewhat confrontational style, are sure to have a big effect on the match.
The forecast is for the weather to clear late this afternoon in Invercargill.
