The Boston Red Sox are in one of the tightest playoff races in years. They started a critical seven-game homestand Monday atop the American League East – with three other teams within four games of first place.

Boston has gotten this far with a roster infused with young players. The “Killer B’s” – Mookie Betts, Xander Bogaerts and Jackie Bradley Jr. – have played a major role in bringing this team back to the top of the division after back-to-back last-place finishes.

You can draw a lot of energy from young players. Trouble is, a youthful roster has its pitfalls, too.

The Red Sox were reminded of that on the trip that ended in Toronto on Sunday. Yoan Moncada began the trip as the latest young prospect providing a late-season spark. But by the end of the week he was firmly planted on the bench – and facing the possibility that he won’t be cracking the lineup again this season.

The 21-year old Moncada appeared as a pinch-hitter Monday night and struck out, tying the record for position players by striking out nine straight times. That’s bad enough. On Saturday, he came in as a pinch runner and didn’t know there were two outs in the eighth inning – retreating to first base on an inning-ending flyout.

“This is a great learning experience for Yoan,” Manager John Farrell told reporters in Toronto. “I think while he got a boost of confidence by coming to the big leagues, you get challenged a little bit and you have to take a step back to rebuild that. Our primary goal is to win. Development in this situation does not take a front seat.”

Moncada seemed to be a leading candidate to make the playoff roster as a 25th man who could serve as a pinch runner in the playoffs, a role Dave Roberts rode to fame in 2004. Now, it’s unlikely Farrell would trust Moncada in that role.

Andrew Benintendi, 22, could be returning this week, and may become the man most likely to take that role. He’s just a year younger than Betts and Bogaerts, yet those two players are considered veterans.

Betts and Bogaerts have combined to play 277 games this season. Betts has become one of the front-runners for the MVP award, having reached base safely in 29 straight games, including Monday. He leads the majors in total bases and multiple-hit games and is near the top of the charts in most hitting categories.

Bogaerts is among the leaders in runs and hits. While he has cooled off over the past month, Bogaerts was still hitting .299 entering Monday and has been a fixture in the second spot in the lineup.

Three years ago, Bogaerts won the starting job at third base in the playoffs, posting an .893 OPS (on base plus slugging percentage). Only World Series MVP David Ortiz had a higher OPS for the Sox that postseason.

That’s a pretty good reminder what young players can do for a team down the stretch. The Red Sox know they need all hands on deck, but also realize that youthful mistakes can’t be commonplace at this point of the season.

Tom Caron is a studio host for the Red Sox broadcast on NESN. His column appears in the Portland Press Herald on Tuesdays.