Davies started at centre-half as Boro's reserves beat Grimsby 4-1 in a totesport.com league game at Billingham.
The Stockton-born defender, who made more than 60 Middlesbrough appearances before leaving the club in 2007, has spent the last month training at Rockliffe Park.
He remains on the books of Stoke City, but Potters boss Tony Pulis recently told him he is surplus to requirements at the Britannia Stadium and instructed the 26-year-old to seek employment elsewhere.
That resulted in him returning to the North-East, and Mowbray must now decide whether or not to offer a permanent deal.
Stoke are not seeking a fee for Davies, but wages could present a significant problem, with the Teessider understood to be earning around £18,000-a-week in the Potteries.
Boro will not be offering anything like that if they opt to step up their interest, but Davies desire to rejoin his hometown team could yet result in a compromise being reached.
Mowbray's need for a defensive addition will increase if David Wheater completes an anticipated move away from Teesside this month, but the Boro boss had been unwilling to table a formal offer before he had the chance to see Davies in a competitive environment.
That finally happened yesterday, and while the defender was hardly tested as Boro's second-string recorded a comfortable victory, a decision is expected before the weekend.
"Andrew's been with us for more than a month now, and while the arrangement has suited both parties so far, that can't go on forever," said Mowbray. "It's been difficult because weve been wanting to see him in a match situation, but first the training ground was covered in snow, then it was the Christmas period and there werent really any reserve games.
"You can't really get a proper idea about somebody until you've seen them in a game, but we'll have to make a decision eventually."
Davies played the full 90 minutes yesterday as a Boro reserves side featuring Durham City goalkeeper Lewis Graham in the absence of both Jason Steele and Danny Coyne cruised to a routine win.
Jonathan Franks and James Gray scored two goals apiece, with full-back Dwayne Samuels grabbing a consolation for the Mariners.
While Davies could be returning to the Riverside permanently, Matt Kilgallon will not be rejoining Boro for a second spell after signing a season-long loan deal with Doncaster Rovers yesterday afternoon.
Kilgallon joined Middlesbrough on loan at the start of the season, but returned to his parent club, Sunderland, when a long-standing back problem failed to clear up.
The terms of his initial loan meant Boro could have requested his return once Sunderland's medical staff deemed him fully fit, but Mowbray has opted not to take up the opportunity.
Instead, the loan agreement between Boro and the Black Cats has been nullified, and Kilgallon has joined Doncaster for the remainder of the campaign.
Kilgallon's contractual status has shifted on a number of occasions this season, but that is nothing compared to the uncertainty that has surrounded Mido.
The controversial striker is back in the North-East following a dispute with Dutch side Ajax, and is expected to continue training with the rest of the Middlesbrough squad for the next few days.
His future beyond the end of the month remains uncertain, and to a large extent will depend on how the current impasse between the Egyptian and Ajax is resolved.
However, it is not out of the question that he will make a surprise return to the Boro first team in the final five months of the season.
MIDDLESBROUGH RESERVES: Graham, Shead, Otte, Davies, K Edwards, Weldon,
Smallwood, Halliday, Park, Franks (Roushias 86), Gray.
Source: Northern Echo
Source: Northern Echo