Ubaldo Jimenez has changed up his pitch selection

Last season, Ubaldo Jimenez was demoted from the rotation in the first year of his four-year contract with the O’s. Many fans were dissatisfied when Jimenez was named the last member of the rotation out of spring training this season, ahead of Kevin Gausman. So far this season, he has quieted those critics. He has done it with a drastic shift in his pitch selection. Let’s take a deeper look to see if his resurgence is sustainable.

So far this season, Jimenez has increased his sinker usage by more than 10% at the expense of four-seam fastball and slider. This is not an aberration but a trend. Jimenez has increased his sinker usage for the last three seasons. This can be seen as Jimenez’s way to deal with his declining velocity. Five seasons ago, he averaged more than 96 mph with both his sinker and four-seam fastball. This season, he is averaging about 91 mph with both his sinker and four-seam fastball.

Are more sinkers better for Jimenez’s performance? Here are the results of Jimenez’s pitches over the last three seasons.

There does not appear to be any significant difference between the results on his four-seam fastballs and his sinkers. Four-seam fastballs induce more swing-and-misses and pop-ups, but sinkers generate more groundballs. Overall, the results on the pitches are almost identical, with batters hitting .263 and slugging .410 off his four-seam fastballs, and hitting .270 and slugging .442 of his sinkers. Both his four-seam fastball and sinker also get called for strikes and ball about the same percentage. If anything, past results show that he should be using his four-seam fastball more often.

Jimenez has definitely changed as a pitcher over the last few seasons, relying more on his sinker at the expense of his four-seam fastball. This season has seen an especially dramatic increase in his sinker usage. However, there does not appear to be any advantage to be gained with using more sinkers. We cannot explain his early season success based on his change in pitch selection. We can only hope that whatever is driving his success early this season is sustainable and not just plain randomness.