The Englishman is under some pressure after his side lost 3-1 to Fulham at the weekend.
Striker Alexander Isak was starved of service in the game, only touching the ball 26 times.
Howe said: "He’s not as involved as we want him to be, he’s not having the impact in the games we want him to have and what he is capable of doing so hence the tactical reshuffle at half-time."
He then added: "I thought we were better in the second half so there is a degree that the substitutions helped us at that stage, maybe not the latter ones where I thought our performance tailed off in the second period."
"I thought Lewis Hall did really well and Jacob (Murphy) of course set up the goal. There was a much better feel about the group in the second half. Fabian's (Schar) chance is probably a key moment in the match. It could have been different for us but it wasn’t to be."