While Red Sox eyes are watching the development of third baseman Rafael Devers, other prospects are performing for the Portland Sea Dogs.

They came through Saturday in a doubleheader split against the Reading Fightin Phils at Hadlock Field. Portland won the first game 5-0 and lost the second, 2-0.

Devers made his presence known with a grand slam in the first game.

As did Jalen Beeks (4-1), who threw five shutout innings in Game 1, allowing two hits and two walks, striking out eight. Ty Buttery followed with two perfect innings of relief with two strikeouts. Buttery, whose fastball touched 98 mph, lowered his ERA to 1.98 and his WHIP to 0.88.

Tzu-Wei Lin went 3 for 6 in the two games, playing shortstop in the first game and center field in the second. He leads the team with a .353 average, fourth-best in the league.

Reliever Williams Jerez threw two scoreless innings in Game 2, allowing one single and striking out two. Jerez, with a 95 mph fastball and improved slider, has a 0.66 ERA.

Amid the prospects was Boston Red Sox utility player Brock Holt, making a rehab appearance in Game 1. Holt, who is on the disabled list with vertigo, was the designated hitter for the Sea Dogs and went 1 for 3, with a line single to right in the first inning.

During the rain delay in the first game, Holt left the game and the ballpark. He was not available for comment. Holt’s next scheduled rehab is Monday in Pawtucket.

Holt popped out in the second inning, when the Sea Dogs scored all their runs. Cole Sturgeon singled in one run before Devers came up with the bases loaded and got a 1-1 change-up from Shane Watson (2-2). Devers jumped on it, sending it an estimated 426 feet to straightaway center. The exit velocity was 103 mph.

The grand slam gave Portland a 5-0 lead, which was plenty for Beeks.

Using a fastball in the 92-93 mph range, Beeks retired the first nine batters he faced. He now has 34 strikeouts, tops in the Eastern League. Beeks is also tied for first in wins and lowered his ERA to 1.63.

Beeks threw 91 pitches. He might have been able to pitch into the sixth, but the game was delayed 1:10 by rain. Buttery took care of the rest.

In the second game, Scott Kingery led off with a triple against Portland starter Taylor Grover (1-1). Kingery scored on a wild pitch.

That was the winning run as Portland amassed only three hits against three Reading pitchers. Yacksel Rios (1-1) got the win.

Reading scored again in the seventh as Jamie Callahan gave up only his second earned run of the season. A single, fielder’s choice and wild pitch put Mitch Walding on second base. After a strikeout – Callahan’s 17th in 11 innings – Jorge Flores hit a bloop to left field. Danny Mars slipped as he charged the ball and couldn’t reach it. Walding scored.

Portland is 15-9, one game behind Trenton in the East Division. Reading is 14-11.

NOTES: The announced paid attendance was 4,470. … Infielder Jose Rosario was activated from paternity leave and sent to Triple-A Pawtucket. … Lin played center for the second time this year. He handled two line drives easily. … Infielder Deiner Lopez, recently called up from Salem, played both games and went 2 for 5. … How good is the Sea Dogs’ bullpen? Buttrey’s 1.98 ERA is fifth-best among the relievers, behind Austin Maddox (0.00), Jerez, Callahan (1.64) and Luis Ysla (1.64). … The teams meet at 1 p.m. Sunday. Trey Ball (1-1) will start for the Sea Dogs. In his last start, Ball threw six shutout innings at Hartford.

Kevin Thomas can be reached at 791-6411 or:

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Twitter: @ClearTheBases