Middlesex 356 lead Hampshire 209-4 by 148 runs
The Hampshire opener is making his first Ageas Bowl appearance in the Championship since he was diagnosed with cancer last June.
Carberry put his side in a strong position as they replied to Middlesex’s 356 – as they ended the day 148 runs in arrears with six wickets remaining.
His blocking and leaving, especially against the troublesome Roland-Jones in his first spell, helped forge partnerships with Jimmy Adams, Liam Dawson and Sean Ervine.
The and Adams put on 57 before his opening partner edged Ollie Rayner to James Franklin.
The same two Middlesex players reversed their roles to see off James Vince – the England man tempted too far into the corridor of uncertainty to find a thick edge, kicking the ground on his exit.
Carberry’s fifty came from 154 balls – brought up with a stinging cut to the boundary,
Liam Dawson was not best pleased when umpire Jeremy Lloyds lifted his finger to the last ball before tea, with the batsman adjudged to have tickled one behind off Rayner.
His longest standing partner turned out to be Sean Ervine – with the pair scoring at the quickest rate of a slow-going day.
The Zimbabwean scored a 70-ball fifty and like Dawson appeared impenetrable until Finn returned to the attack with six overs left in the day to make him play on.
Kyle Abbott, in as nightwatchman because of Rilee Rossouw's chipped finger, looped a simple chance to Sam Robson at gully but the ball somehow hit the turf.
Earlier, Middlesex were bowled out for 356 – with Brad Wheal ending up with figures of four for 98 for the hosts.
Abbott had the first of the four wickets left over from the first day – when he found James Franklin feeling a foot outside off-stump – the ball daggering to James Vince at third slip.
And despite Roland-Jones hurrying the tail with an exhilarating 38, Wheal accounted for him when he nicked to second slip, Dawson pinned Rayner, before the Scotland international had Steven Finn leg before.