The 32-year-old attacker has been restricted to 11 appearances in all competitions in 2018/19, with only six of those coming in the league.
With Phala’s contract at SuperSport set to expire at the end of June, he looks to be on his way out of the club amid reported interest in his services from Orlando Pirates, Bidvest Wits and Highlands Park.
"He has played bits and pieces," Tembo said.
"There are also other youngsters coming up like Kamo [Mahlatsi] and [Jamie] Webber and competition will always be tough."
"I treat players equally and all deserve opportunities."
Meanwhile, Matsatsantsa are yet to engage with midfielder Reneilwe Letsholonyane over his future at United.
The 36-year-old’s deal at the club will also expire at the end of the season.