Haaland gestured to Norway's bench that he needed to come off and was replaced in the 67th minute of the 2-1 loss in Porto on Sunday. He was seen limping on the field before the substitution.
Speaking after the match, Solbakken did not say Haaland had sustained an injury but discussed the heavy workload the striker had been facing. Haaland had played the full game in each of Norway's first three Nations League fixtures against Denmark, Portugal and Wales, following a busy start to the English season with City and a run to the World Cup quarterfinals with Norway over the summer.
"He was tired against Wales. That's why we had a heart-to-heart conversation yesterday. We went through the possible options," Solbakken said in quotes carried in Norwegian media.
"He might have played the last 45 minutes against Portugal. That was a discussion. But he has very bad vibes and feelings about it. I am very pleased that he managed to pull out 60 good minutes."
Haaland did not score against Portugal or Wales, the two games Norway has played since the verdict by an independent commission on Manchester City's financial case was published. He had scored in the first two matches of the international break and has 65 goals in 59 appearances for his country.
Haaland is understood to be the only senior out-and-out striker in City's squad as the club returns to league action under the cloud of a financial scandal.