The 28-year-old was on Steve Evans' radar as he looked to bolster his attacking ranks, the Yorkshire Evening Post reports, but the Norwich City striker ultimately ended up joining Birmingham City on loan.
And after lining up against his international teammate on Tuesday - with Dallas' two goals helping the Whites come away from St Andrew's with a 2-1 win - the former Brentford winger conceded that it would have been great if United had managed to get a deal across the line.
"I'd have loved it if we'd have had Kyle at Leeds but Coops [Liam Cooper] and Sol [Bamba] were magnificent. They didn't let him play. He's a dangerous player and if you let him play he can be lethal," he told the Yorkshire Evening Post.
While the former Rangers man was kept quiet by Leeds' centre-back pairing, it seems likely that had he moved to Elland Road he probably would have been a welcome addition.
His record at club level is not overly impressive, but his recent form for Northern Ireland has been sensational, and with Leeds' strikers struggling for goals at times this season, Evans may have been hoping to see the forward that terrorises teams on the international stage potentially drag United back into play-off contention.
But with Dallas proving in midweek that he is capable of some wonderful finishes, the fact that the Whites failed to sign Lafferty may be slightly easier to accept, especially if the winger can score those kind of goals on a regular basis next season.