Lukaku played only the final seven minutes of last week's 2-0 Nations League win over Italy in Rome and remained on the bench during Monday's last-gasp home defeat by France.
His limited role raised questions over the international future of the 33-year-old, who has scored 93 goals in 133 appearances for Belgium.
"It is absolutely not the case that Romelu cannot come on or start. Quite the opposite,” Van Bommel told a press conference on Thursday ahead of the match in Liege.
"It depends on what we think we need in a particular phase or situation. He has certain qualities, but I felt that in that match we were playing a little further away from goal, which meant we could use pace. The only disadvantage is that he hasn’t played much for Fenerbahce."
Lukaku has had little playing time at club level recently. Injury and a disagreement with Napoli meant he did not start a match last season and made only a handful of substitute appearances.
Since joining Fenerbahce, he has started one game and been brought on as a substitute seven times.
“You have to take that into account," Van Bommel said.
"I also explained to him that I chose pace, not because he is doing badly, because he is training well. But it’s not the case that you play based on good training sessions, or vice versa. But you don’t need to read anything major into it.
“As a player, you always want to play. We have 24 outfield players, which is more than usual. Don’t worry about it. Romelu has experienced everything. He hasn’t always played at his clubs and has sometimes had to fight for his place. No worries,” the coach repeated.
Belgium will be cautious about the workload of 22-year-old Chelsea midfielder Romeo Lavia, who made his first international start against France and earned rave reviews for his performance.
Lavia has struggled over the last three seasons with frequent injuries.
"Romeo came on against Italy and played 85 minutes against France. He did a fantastic job," said Van Bommel.
"You can already assume that I won’t start him. Chelsea are also being cautious with him, and so are we. We want to make the most of his qualities."