The Tykes returned to winning ways last time out to climb into fifth, while Boro are nine points off the playoffs following a three-game winless streak.
After losing 2-1 to Sheffield Wednesday and drawing 1-1 with Reading at home either side of the two-week break, Barnsley beat Luton Town 2-1 on Tuesday to pick up a welcome win - a record sixth in a row away from home.
Daryl Dike maintained his superb form since joining on loan from Orlando City in January with a goals in both halves, making it seven goals in 13 outings for the American forward.
That win maintained Barnsley's two-point lead on Reading in sixth and a three-point advantage on seventh-placed Bournemouth, who have a game in hand to play.
Barnsley cannot afford to slip up this weekend, then, particularly given that victory for Boro would revive their own top-six hopes.
Neil Warnock's men have stuttered of late, taking just one point from the last nine on offer - defeats to Millwall and Bournemouth followed by a 1-1 draw against Watford.
Promotion expert Warnock has effectively ruled out a place in the playoffs, but his side could be within six points of sixth place should results go their way this weekend.
This is the toughest of the Smoggies' remaining fixtures, and Warnock knows better than any manager in the division just how important momentum can be at this stage of the season.
However, Boro have lost each of their last three away league games and have lost five of their last seven away league meetings with Barnsley.
Dyke has scored four goals in his last four appearances for Barnsley, netting braces at both Wycombe Wanderers and Luton, and is certain to lead the line here.
Bolasie replaced Morsy in that match and took his opportunity with a late leveller, meaning that he is likely to get the nod out on the left here.
Warnock has never been entirely happy with his striker options this term, but Duncan Watmore may again get the nod over Ashley Fletcher up top on Saturday.
Barnsley possible starting lineup:
Collins; Andersen, Helik, Sibbick; Brittain, Palmer, Mowatt, Styles; Morris, Dike, Woodrow
Middlesbrough possible starting lineup:
Bettinelli; Fisher, McNair, Hall, Bola; Howson, Saville; Spence, Kebano, Bolasie; Watmore
We say: Barnsley 2-1 Middlesbrough
Middlesbrough won October's reverse fixture 2-1 and are seeking a first league double over Barnsley since the 2011-12 campaign.
The hosts are a completely different side six months on, though, even if they have been shaky at Oakwell of late, and we can see them picking up all three points here.
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