"Krishna was quick with close technical skills and an eye for goal, and when I researched his record I was impressed.
"He seems the sort of player capable of taking the next step and scoring goals in the A-League."
The record Merrick was speaking about shows Krishna has scored 14 goals in 22 appearances for Fiji, while at Waitakere United, who he joined in 2008, he netted 72 times in 103 appearances.
In the Oceania Football Championships he scored 16 goals in 27 games, while in the Northern League it was 17 in 32.
Despite that impressive record, Krishna shouldn't expect to walk straight into the Phoenix' starting XI.
"At the Phoenix everyone works hard to get a place in the starting team," Merrick said.
"If you do well at training you get on the bench; come off the bench and do well and you get a start.
"Roy will get every opportunity; it is up to him now to grasp it."
Krishna will train with the Phoenix for the first time on Wednesday.
Northcote City striker Milos Lujic has also joined the Phoenix, signing a two-week contract as a replacement for Reece Caira who is in Oman with the Australian under-22 squad.
Lujic, 23, scored 19 goals in Northcote City's title-winning campaign last season, earning him a reputation as one of the most lethal strikers in the Victorian Premier League.
Lujic trained with the Phoenix squad for the first time on Monday.
The Phoenix host the Central Coast Mariners in Wellington on Sunday.
