Mercado is expected to serve as a bulk reliever behind opening pitcher Orion Kerkering in Sunday's game against the Athletics, Tim Kelly of PhilliesNation.com reports.
Manager Rob Thomson announced Tuesday that Mercado was being moved to the bullpen, but because Zack Wheeler (back) is unable to take the hill for the Phillies' final game before the All-Star break Sunday, Mercado will end up serving as the club's de facto No. 5 member of the rotation to close out the first-half schedule. Though Kerkering is drawing the start, he hasn't recorded more than five outs in any appearance this season and is unlikely to work more than an inning or two before turning the game over to Mercado. Through his first three big-league outings (two starts), Mercado has given up six earned runs on seven hits -- including three home runs -- and five walks while striking out six across 7.2 innings.