"He pulled up really well, and I thought he looked really good on the weekend," Roos said of Malceski.
"Having that break and a couple of weeks under his belt … certainly he looked like the player we expect (him to be)."
While Malceski continues to make progress, Roos was less optimistic about star forward Michael O'Loughlin, who missed round 22 with an ankle injury.
Roos described the 31-year-old as very doubtful for the second elimination final against North Melbourne this weekend.
Malceski's inclusion in the Swans' side against the Lions was only his second match in the last eight. While he played against Geelong in round 20, a calf injury has largely kept last season's best and fairest on the sidelines.
Malceski finished Saturday night's clash with 27 disposals, with a long bomb after gaining possession and bursting through the centre of the ground early in the game a sign that the 24-year-old was returning to his best.
Roos was generally satisfied with how the Swans were progressing ahead of Saturday night's do-or-die clash.
"Going into last weekend, we had some objectives that we wanted to meet, and we've pretty much met all those objectives in terms of Adam [Goodes] having a rest. Ryan [O'Keefe] will be back after being rested with the 'flu, so he'll back better than before.
"Defensively, we're a lot better, and offensively we tackled a lot better. We certainly go into this game with a lot more confidence."
