With his squad shaping up for the forthcoming season, the United manager Adkins is still looking to bring in another central midfielder and will offer the left-back Lea a deal to stay with United after a successful trial.
"He's done very well. I'm delighted with him," adkins told the club's official site.
"We've had him for two weeks now and I'm very happy with what I've seen from him."
The trialist central midfielder James Sherman may still be offered a short-term deal after impressing in the two friendlies so far.
However the United boss is keen to keep his options open ahead of the season kick off on August 9.