The catcher, who served as Class A Lansing's DH on Thursday night, could have watched a few pitches, collected his thoughts and eased his way back into game action.
But he did the opposite.
Pentecost swung at the first pitch he saw and turned it into an RBI single.
The hit, as it turned out, was not a fluke and instead of showing rust from the time off, Pentecost showed why he was the 11th overall selection in 2014 as he went 3-for-4 with a homer and two RBIs in a 5-0 win.
The rest of the best prospect performances from Thursday
• After a slow start, some may have had questions about White Sox No. 2 prospect Tim Anderson. Not anymore. Anderson extended his hitting streak to five games and went 4-for-5 with a homer and scored four runs Thursday in Triple-A Charlotte's victory. The No. 43 overall prospect has seven hits in his last 10 at-bats and multiple hits in four of his last five games.
• After posting two multi-homer games in 2015, Astros No. 9 prospect Derek Fisher turned in his first such performance of 2016 on Thursday night, going 2-for-4 with two homers and three RBIs in Double-A Corpus Christi's win. Fisher's second homer was a walk-off shot. He has seven homers this season, including four in the past four games.
• Renato Nunez is not known for his speed. The Athletics' No. 5 prospect has eight triples in 472 career games. However, Nunez put his legs to the test Thursday afternoon when he legged out an inside-the-park grand slam for Triple-A Nashville. The grand slam -- part of a 3-for-4 game with four RBIs -- was Nunez's seventh homer of the season.
"The ball almost got out; it hit the wall and I was just running hard.," Nunez told MiLB.com. "Then I see the outfielder with his hands up and I cannot see the ball, [but] the ball was in play so I kept going to score and wait for the umpire. I was always running and didn't stop."
• Braves No. 13 prospect Mike Soroka turned in another scoreless start Thursday. The right-hander fired 5 2/3 scoreless frames in Class A Rome's 3-0 win over Hickory, the fourth time he's blanked his opponent in seven starts this season. Although Soroka has been pitching well, his first professional win was tough to come by, so the 18-year old was thrilled to finally collect his first W.
"It's definitely an experience that I'll probably remember forever," Soroka told MiLB.com. "Our offense did what they needed to do and our relief pitchers shut it down. I couldn't ask for a better team effort."
• A single is not usually thought of as the most difficult part of a cycle, but that was all that eluded Dustin Peterson on Thursday. The Braves' No. 21 prospect had a chance for the cycle in his final at-bat, but struck out and finished the evening 3-for-4 with a double, triple and homer in Double-A Mississippi's 4-1 win.
• Home runs are starting to become routine for Dylan Cozens. The Phillies' No. 23 prospect hit a solo homer and went 1-for-3 in Double-A Reading's win over Trenton. Cozens has now homered in three straight games and five last of the last six.
• Ricardo Pinto had a no-hitter through six and finished with seven scoreless innings on the evening. The Phillies' No. 10 prospect struck out five and surrendered just two hits and a pair of walks in Reading's 3-0 shutout.
• The bad news for Phillies fans? Alec Asher's scoreless streak came to an end. The good news? Philadelphia's No. 27 prospect gave up one earned run on six hits in 6 2/3 innings for Triple-A Lehigh Valley. The right-hander's scoreless streak came to a halt after 28 1/3 innings as Asher continues to dominate Triple-A competition. In three starts since his promotion, Asher is 3-0 with a 0.40 ERA.
• Rays No. 30 prospect Riley Unroe set a career high for hits as he went 4-for-5 and extended his hitting streak to six games for Class A Advanced Charlotte. He credits his fast start to a new approach at the plate.
"I've been able to flush out every previous at-bat, whether it was good or bad," Unroe told MiLB.com. "It's awesome to see it working because I spent a lot of time with my dad [former Major Leaguer Tim Unroe] this offseason on understanding that lesson and treating games pitch by pitch."
• Alec Mills continues to show off his strong control as he put together another quality outing. The Royals' No. 14 prospect threw six scoreless innings Thursday night, striking out eight and giving up just three hits and one walk for Double-A Northwest Arkansas. Mills has walked just six through 44 innings this season and has issued just 60 free passes in 308 2/3 career innings.
• Brett Eibner had a game to remember as the Royals' No. 23 prospect went 3-for-5 with three homers and six RBIs in Triple-A Omaha's 15-5 win. The trio of homers set a new career high for Eibner, who now has six career multi-homer games.
• After a pair of tough outings, Ian Clarkin's Thursday afternoon start for Class A Advanced Tampa reminded everyone why the Yankees made him a first-round selection in 2013. The No. 10 prospect in New York's system fired seven scoreless innings, gave up just five hits, walked none and struck out 10, setting a career high.
"It was good, it was good. It was a long time waiting," Clarkin told MiLB.com. "I had a lot of strikeouts in my high school days, and to say I've been waiting for a day like this for a while -- it's always nice to have everything just going your way."