With September roster expansion just around the corner as the Twins prepare for their stretch run, there's plenty to discuss about top prospects who could have an impact at the Major League level, the current difficulties for the starting rotation and how all of those pieces might fit together in September.

There were also several questions for this week's Twins Inbox asking about a possible playoff rotation and still others inquiring about rotation options for next season, but let's hold off on discussing that for now. There are still two more Monday off-days remaining in September, after all.

Let's dive in.

Zack Littell, followed by Trevor Hildenberger.

Anything that the Twins potentially get from top prospects Brusdar Graterol and Jorge Alcala in September would be gravy, since the two youngsters are unproven commodities at the Major League level. It's difficult to immediately cast on them the expectation of making strong contributions to a playoff team, though that's certainly not out of the question and would be a welcome addition to the bullpen.

On the other hand, Littell and Hildenberger are proven Major League relievers who have already contributed in meaningful ways to this team's success this season. Littell is in Triple-A Rochester due to a tough roster crunch right now, but he has earned his roster spot and has only allowed two runs in 17 relief appearances since June.

Hildenberger's numbers weren't necessarily pretty before he was optioned to Triple-A earlier this season, but a difficult May masks the fact that he was extremely effective in April, particularly in getting one or two outs to escape jams. The sidearmer could complement Tyler Duffey well in that role upon his return.

Graterol, the Twins' No. 3 prospect, could indeed be an internal option to be called up, as could Alcala, who is ranked No. 23 on the Twins' list by MLB Pipeline. Since both pitchers were moved up to Triple-A Rochester just over a week ago, Graterol has allowed no runs and just three hits in 3 1/3 innings with four strikeouts and a walk, while Alcala has given up one hit and no runs in four innings with five strikeouts and a walk.

So, at least in the early stages, the 21-year-old Graterol, who lives in the triple digits with his fastball, and the 24-year-old Alcala, who throws in the high 90s with movement, have adjusted well to more advanced hitters.

I also have my eye on outfielder Ian Miller, who was acquired under the radar from Seattle in August and has 34 stolen bases this season to go with a quietly productive bat. He could be an interesting pinch-runner/defensive replacement option to stash on a playoff roster.

Reminder: A player must be on the 40-man roster by the end of the day on Aug. 31 to be eligible for the postseason. The Twins' 40-man roster is currently at 39.

It's no secret that José Berríos is working to correct some mechanical issues right now. The results certainly haven't been pretty in his last four starts as he makes those adjustments in the heat of a playoff chase, but remember how rough of a stretch Miguel Sano also had earlier in the summer while he, too, was making some adjustments to his swing?

The thing is, Berrios does appear to be making progress. He spoke after his start in Texas on Aug. 17 that he was using his lower half better in his delivery to generate more fastball velocity. His four-seam velocity has hovered around 93-94 mph for his career, and it has been back up to 93.6 and 93.7 in his last two starts after hanging around 91-92 for three starts.

Now, though that fastball velocity is back, Berrios just needs to make the tweaks that will help him execute his locations more consistently. He said after his last start that he's still working to keep his front shoulder more closed during his delivery. Recall that Berrios made mechanical adjustments in Spring Training, too, and had some tough results, though he emerged ready to go at the start of the regular season.

Twins manager Rocco Baldelli has said that this could be a consideration in September, and it doesn't hurt that the Twins have two well-placed Monday off-days in that month to break up the schedule a bit. Roster expansion should also help get some of the starters extra rest, since four Triple-A starters -- Lewis Thorpe, Devin Smeltzer, Kohl Stewart and Randy Dobnak -- are on the 40-man roster and should be up with the team in September.

Whether it's having one of those young guys make a spot start once in a while or keeping the Major League starters on a lower pitch count since long relief help will be plentiful, having all hands on deck in the pitching staff should go a long way in keeping the load off for the Twins' core five rotation options.

Correct me if I'm wrong, but I feel like you're thinking of the opener or bullpen games when it comes to "creativity" out of the bullpen, but that just hasn't been necessary given the composition of the Twins' roster. This coaching staff always sought to let the available matchup data dictate bullpen use more than any antiquated notion of a "seventh-inning guy," "eighth-inning guy" and a "closer," and that's largely what they've done.

Both Taylor Rogers and Sergio Romo have closed out games. They haven't been three-out saves in several cases. Neither of those guys has been chained to any single inning, nor has Sam Dyson. Duffey has seen plenty of use in lots of different situations and has settled into a flexible "fireman" role. Several different young arms have been shuttled in and out of Rochester to create a rotating long relief role.

That fluidity is what has defined this bullpen all season long.

This ... is taking scoreboard watching to a whole new level, and I frankly respect it. The Twins will keep hitting lots and lots of homers. If the Yankees hit more, so be it.