The 29-year-old will pen a 12-month deal at the Macron Stadium, with the option of another year, after training with the club following his release from Almeria, who were relegated out of La Liga last term.
Lennon had tracked the former Barcelona defender during his time at Celtic and expects him to contend with Dean Moxey for the left-back berth following Tim Ream’s departure.
“Jose Casado has come in this week to provide competition for Dean Moxey,” Lennon revealed.
“Dean’s played really well and is in a consistent mode of form at the minute.”
On Casado, Lennon added: “He’s a very good player. I watched him at Celtic when he was at Vallecano and quite liked the look of him then.
“He had a bad injury but has recovered very, very well. He’s very professional, he’s been in the last 10 days and trained brilliantly. He knows how to play at left-back and I think he’ll be a very good addition to the squad.”
Wanderers, who are yet to win this term and only scored their first goal of the season in the dying embers of the draw with Nottingham Forest last weekend, signed right-back Francesco Pisano last week and will have more defensive depth once Derik Osede and David Wheater return from injury after the international break.
“That’s something that we needed and certainly at the back,” Lennon admitted. “We’ve got that now – now we just need to push the button on goalscoring.”