Phillips, 29, arrived on loan from Manchester City after struggling for regular minutes following his £42 million move from Leeds.
The midfielder made just two league starts for City in 18 months before another limited spell at West Ham last season.
“He’s played a good number of games,” McKenna stated on Phillips.
“With the 10 starts, he’s probably been unavailable for maybe six games or so, six or seven possibly with the suspension and with the niggling ankle injury he had.
“So he’s played a good number of games. I think he’s improving. Of course, we all want things to accelerate really quickly but 10 starts considerably more league starts than he’s made in the last two seasons.
“Ten league starts, I think he’s improving as the season goes on and he’s in a much better rhythm now then when he arrived and hopefully that will continue and he can have a really big impact in the last bit of the season.
“Of course, there’s really good competition in midfield. Jens Cajuste has been excellent, really, when he’s played and has really stepped up and delivered a really high level of performance and Samy (Morsy) is the captain but has been consistent with his performances as well.
“I think Kalvin has shown good qualities over the course of the season and is hungry to help the team and I think is building up to a pretty good rhythm, and we feel he can have a good impact and a good part to play in the next few months.”