Yes, the Angels have only used five starting pitchers this season but that does not mean the unit has been good. Angels starters have a 9.16 H/9 (MLB rank: 27th), a 7.39 K/9 (MLB rank: 26th), a 3.69 BB/9 (MLB rank: 28th) and a 1.43 WHIP (MLB rank: 29th). That's absolutely brutal, especially given how dominant Yusei Kikuchi has been. The Angels' lone All-Star representative leads the starters in virtually every statistic and has been an absolute workhorse -- no one in baseball has more starts than Kikuchi.
José Soriano is a fine pitcher, but he's clearly not good enough right now to be a no.