Furnished with a temporary top with No. 98, Donaldson broke out of an 0-for-15 slump with a pair of long home runs as Oakland's game against Seattle was rained out in the top of the fourth inning with the Athletics ahead 12-1 Friday.
"The last couple of days I've been working on a couple of things in the cage, and the biggest thing for me is just getting comfortable in the box," Donaldson said. "I was able to get pretty comfortable and get a couple of good pitches to hit."
Donaldson hit a two-run homer and a solo shot. Seth Smith and Michael Choice also hit two-run homers for the A's, and Shane Peterson had a solo drive.
None of the stats count because the game wasn't official.
"Everybody had good at-bats, certainly Donaldson," Oakland manager Bob Melvin said. "I don't care if the wind was blowing in or out. They were going out anyway."
Donaldson was asked whether he'll keep the No. 98.
"Well, I mean, everybody seems to want it to, I don't know," Donaldson said. "I don't know if it was the number or not, but I might give it another chance. We'll see."
Donaldson had one hit in his first 20 spring training at-bats coming in. He's trying to win the starting job at third base after ending last season there.
"Toward the end of the year last year, I felt really comfortable over their at third," he said, "and coming into this spring I felt way better than obviously I did last year at the beginning of the spring. I've been able to get into a better routine as far as what I need to do and get ready for the game and get ready for the season."
Donaldson is a converted catcher who had minimal experience at third before last season. He made the 2012 opening-day roster but was sent down to Triple-A Sacramento three weeks into the season due to offensive struggles. It took until August before he settled in at third. All told, he started 71 games and committed 12 errors. He also hit .294 in the AL division series.
"This is all just a process," he said. "It's one game but the good to take away from it is I felt like I stayed within myself, got a couple of good pitches to hit and when I got a good pitch to hit, I got it good."