Thoughts on Detroit Tigers prospect Spencer Turnbull

Tonight the Detroit Tigers will send right-handed pitcher Spencer Turnbull to the mound against the Minnesota Twins for his second major league start. This seem like a good time to answer the following query received last week:

“Spencer Turnbull seems like a sleeper to me but he got hammered in his first start. What do you make of him? I thought he was interesting back in college but he seemed to get lost in the Tigers system”——B.B, Elgin, Illinois

B.B.’s question arrived shortly after Turnbull gave up six hits and six runs in four innings in a start against the Twins on September 19th. Before that Turnbull threw a scoreless inning of relief work against the Cleveland Indians on the 14th. That’s the sum total of Turnbull’s experience in the majors. . .what more can we expect?

As B.B. noted Turnbull was a solid pitcher in college, posting a 2.22 ERA in 93 innings for the University of Alabama in 2014, though some occasional consistency problems as implied by a 61/47 K/BB knocked him down to the second round. He threw hard enough (up to 99) to go higher but didn’t miss enough bats for sabermetrically-minded teams to call his name in the first round.

Turnbull’s tenure in the Tigers system has been decent enough: he holds a 3.59 ERA in 424 career innings over five seasons with a 403/164 K/BB, including a 3.92 ERA in 119 innings this season between Double-A and Triple-A with a 133/46 K/BB. He’s been pretty steady at each level and his component ratios have gradually improved, with a rising strikeout rate as he’s progressed up the ladder.

Listed at 6-3, 215, Turnbull is now 26 years old, not young as prospects go but that’s less critical for a pitcher than a hitter. He’s had some durability concerns, missing much of the 2016 season with a shoulder problem then fighting elbow issues in ‘17.

He doesn’t throw as consistently hard as he once did: in short stretches he gets up to 97 but as a starter he works more commonly in the 91-95 range. He has both a two-seam and four-seam fastball and he’s expanded his secondary arsenal since college, now able to deploy a curve, slider, cutter, and change-up.

While none of his secondaries are especially excellent they’ve improved since college, an observation reflected in his rising strikeout rate. That said, he still relies on his fastballs, which despite some loss of velocity since college retain lively movement. He is a heavy ground ball pitcher and has allowed just 13 home runs in his entire career.

Turnbull is often viewed as a reliever due to a max-effort approach and the history of injury but I think he’s made enough progress with his secondaries to merit consideration as a fourth starter. Overall I think he’s a solid Grade C+ prospect with additional development potential.