Toronto Blue Jays pitcher Ryu Hyun-jin has been forced to leave his start early with a right knee contusion after taking a line drive off his leg.

Ryu was struck by a comebacker off the bat of Oscar Gonzalez of the Cleveland Guardians in the bottom of the fourth inning at Progressive Field in Cleveland on Monday.

The batted ball, with an exit velocity of 97.7 miles per hour, went off Ryu's leg and dropped near the mound. Ryu immediately began limping in pain but had the presence of mind to pick up the ball and threw out Gonzalez to finish off the fourth inning.

After recording the out, however, Ryu dropped to the ground and grabbed his right leg. A few minutes later, he gingerly walked off the field under his own power, but needed some assistance from manager John Schneider to walk down the dugout steps, unable to put much weight on the right leg.

Reliever Jay Jackson began warming up in the bullpen during the top of the fifth inning and took over from Ryu to begin the bottom fifth, with the game still scoreless.

The Blue Jays later announced Ryu had suffered right knee contusion but no further details were immediately available.

It was an unexpected ending to what had been a promising outing for Ryu, who held the Guardians without a hit over four innings while striking out two and walking one. This was Ryu's second start back from last year's Tommy John surgery.

Ryu retired the first 10 Cleveland batters in order, mixing in four pitches to induce soft contact and a couple of strikeouts.

Ryu walked Andres Gimenez with one out in the fourth inning before retiring the next two batters, including the fateful play involving Gonzalez.

Ryu finished with 52 pitches, 34 of them for strikes. Half of those 52 pitches were four-seam fastballs, and he also offered 11 changeups, 10 curveballs and five cutters.

Before the line drive in the fourth inning, Ryu had survived a scare in the first inning, when Jose Ramirez hit a hard comebacker right back to the mound. Ryu got his glove up to his shoulder to deflect the ball and avoid getting hit by the line drive. He promptly picked up the ball and threw out Ramirez to close out the opening frame.

After Ryu left, the Blue Jays used six relievers to hold the Guardians to a run on five hits over the final five innings en route to a 3-1 victory. The Blue Jays have now won four straight games to improve to 64-50.

Ryu remained 0-1 for the season with a 4.00 ERA. (Yonhap)