The Scot has made a host of signings since being appointed as Pepe Mel's successor at The Hawthorns, but is eager to bring in one more new face.
Silvestre Varela arrived on a season-long loan deal from Porto last weekend and Irvine has set his sights on another winger.
"We're hoping to bring in one more signing before the window shuts - another wide player would complete the balance of the squad," he said.
Irvine revealed that Varela and and two of his other new recruits - Joleon Lescott and Georgios Samaras - will miss Saturday's Premier League clash at Swansea City.
"Varela won't play any part on Saturday; he’s not fit," said Irvine.
"He's going to need the international break to have a mini pre-season.
"Neither Samaras nor Lescott will be fit for the weekend.
"The fact is none of them have had a pre-season."
Left-back Sebastien Pocognoli, another close-season signing, is a doubt for the clash at the Liberty Stadium after missing training on Thursday due to a thigh injury.
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