Middlesbrough head coach Kim Hellberg says that Hayden Hackney is "progressing" but he will not be ready to start Saturday's play-off semi-final with Southampton (12:30 BST).
Named Championship player of the season at last month’s EFL Awards, Hackney has not played since injuring his calf against Bristol City on 14 March.
Since the 23-year-old midfielder last played, Boro slipped from second place to finish fifth, leading to their play-off meeting with Saints.
But Riley McGree will be available to start the first leg at the Riverside. The Australia international played the second half of last Saturday's draw at Wrexham after a three-week absence.
"Hayden is progressing, he's getting better every day," Hellberg told BBC Radio Tees.
"Riley is ready to go. There's competition for him, but he's ready."
Hackney's absence has been keenly felt by Boro after he went off when his side were beating Bristol City.
They conceded a last-gasp equaliser in that game without him and proceeded to win none of their next five matches as the chances of automatic promotion faded.
Hellberg is optimistic that his star midfielder may feature at some point on Saturday or in Tuesday's second leg at St Mary's.
"Hayden has been on the pitch for the first time on the grass, so that's a big step forward," the Swede added.
"Then if it's possible to have him on the bench for Saturday, we'll see. Then if it's possible on Tuesday."
'Tough times losing big players'
Hackney is not the only key player that Boro have lost during the run-in.
Top scorer Morgan Whittaker did not feature in five of the seven winless games across March and April, while defender Alfie Jones has been absent since Christmas after ankle surgery.
But Hellberg is thankful how Redcar-born Hackney has shrugged off personal disappointment to maintain a positive presence in and around the squad.
"Of course it's tough for him at the end of the season where it matters most, we lose the league's best player," he added.
"We've had a lot of tough times losing big players through the season, now Hayden has been fighting with that and he's done absolutely brilliant in how he's reacted.
"He's been amazing in trying to support the team in any way he can."
