Turnbull placed on injured list, Mercado will fill fifth spot in lineup

There are countless reasons why the Phillies reached the mathematical midpoint of the season Thursday night with the best record in baseball, but none is more important than the health of their roster.

They’ve only used six different players since Opening Day, which is unusual.

Sorry. Update: By next week, it will be seven.

Righthander Spencer Turnbull, who lasted just three innings in Detroit on Wednesday, was placed on the 15-day injured list with a right lateral flexor strain. He is expected to miss six to eight weeks. He was starting in place of right-hander Taijuan Walker (right index finger).

Manager Rob Thompson said before Thursday’s game against the Marlins at Citizens Bank Park that 25-year-old Michael Mercado, who pitched a scoreless inning against the Tigers after being called up from Class C Lehigh Valley, will start fifth. He is likely to make his major league debut Tuesday against the Cubs at Wrigley Field.

Meanwhile, reliever Yunior Marte was called up from Lehigh Valley to replace Turnbull on the roster.

This development is further evidence of the old adage that a team can never have too many offers. For much of the season, there was public debate over whether Walker or Turnbull should be the fifth starter, especially after Turnbull opened the season by going 2-0, 1.78 while Walker recovered from shoulder soreness.

Losing two games in the space of a week means handing the ball to an inexperienced right-hander and hoping for the best.

Meanwhile, the Phillies are knocking on wood when they realize that their top four starters — Zack Wheeler, Aaron Nola, Ranger Suarez, Sanchez — haven’t missed an inning all season.

Mercado had a 1.71 earned run average for the Iron Pigs in 14 games, 10 of which were starts. He had 44 strikeouts in 47.1 innings while allowing just 31 hits. There’s another reason to suspect he might be fine. He is one of three pitchers now on the Phillies’ active roster who were acquired from the Tampa Bay Rays, the other two, Christopher Sanchez and Jose Alvarado, having excelled this season.

“(Mercado) has a great arm. He’s got a lot of power. He runs the ball very well and strikes out. The inning he threw (in his major league debut) in Detroit was very quiet. I liked the way the ball came out,” Thompson said. “His hand and the way he attacked hitters and threw strikes.”

The manager added that he does not expect his pitch limit to be restricted.

Thompson added that there is no timetable for Walker’s return. He has consistently said he needs to be healthy enough to throw the ball effectively.

When asked about the depth remaining behind Mercado, the manager mentioned right-handed pitchers Tyler Phillips (7-3, 5.02) and David Buchanan (4-3, 5.19).

“It’s a long year and you can see that all over the league. There’s a lot of pitchers that are leaving,” he said. “A lot of position players, too. It’s tough. One hundred and sixty-two. So you’ve got to have depth and our front office has done a great job of providing that for us. We’ve just got to keep moving forward.”